Name: engineered 3d silk-collagen-based model of polarized neural tissue
Uploaded: 2015-10-23T14:00:00.000+00:00
Duration: 6 min 17 s
Description: Watch this Scientific Journal Video about Engineered 3D Silk-collagen-based Model of Polarized Neural Tissue at JoVE.com

We thank the laboratory of Dr. Stephen Moss for providing embryonic rat brain tissues. M.D.T. designed the original protocol. This work was funded by National Institutes of Health P41 Tissue Engineering Resource Center Grant EB002520. K.C. was supported with Postdoctoral Fellowship from German Research Foundation (DFG) (CH 1400/2-1).

뇌 조직 분리 프로토콜은 터프 츠 대학 기관 동물 관리 및 사용위원회의 승인과 관리 및 사용 실험 동물의 (기관 동물 관리 및 사용위원회 B2011-45)에 대한 건강 가이드의 국립 연구소에 부합했다. 1. 실크 비계 준비 <ol><li> 누에 나방의 고치에서 실크 용액의 조제는 이전에 19, 20 설명한대로. <ol><li> 가위를 사용하여 8 개의 동일한 조각으로 각각의 누에 고치를 잘라. 조각난 고치 5 g을 약 11 고치를 사용합니다. (15 분) </li><li> 0.02 M 나 2 CO 3 용액 2 L를 준비하고 핫 플레이트를 사용하여 끓여야 가져. (15 분) </li><li> 조각난 고치의 5g의 무게를 30 분 동안 나 2 CO 3 용액을 끓인다. 주걱으로 끓는 실크에게 분에 한 번씩 저어. 또한 디 씹고라는이 단계는 친수성 ​​단백질 sericins에서 실크 피브로인 정화. (30 분) </li><l난&gt; 손으로 피브로인을 짜서 남아있는 세리신 및 화학 물질을 씻어 증류수에 적어도 세 번을 씻어. (5 분) </li><li> 페트리 접시에 젖은 피브로인을 놓고 흐름 후드 O / N에서 피브로인 추출물을 건조. </li><li> 다음 날은 건조 피브로인 질량의 무게와 유리 비커에 피브로인을 배치합니다. (15 분) </li><li> (4)에 의해 건조 피브로인의 질량을 곱하여의 LiBr 9.3 M의 LiBr 용액 (ML)에 필요한 양을 계산에 피브로인을 용해하기 위해 천천히 실크 피브로인 위에의 LiBr 용액을 붓고 주걱을 사용하여 모든 피브로인 섬유 젖어. 증발을 방지하고, 섬유를 용해 할 수 있도록 4 시간 동안 60 ° C에서 배치하는 비이커 커버. (15 분) </li><li> 주사기를 사용하여, 비커로부터 피브로인 용액을 수집하고 3500 MWCO 투석 카세트에 적재. 48 시간 동안 증류수에 대해 투석을 수행합니다. 물을 시간의 각 한 쌍을 변경합니다. </li><li> 주사기를 사용하여, 발 피브로인 수용액을 수집20 분 동안 4 ℃에서 9,000 RPM (~ 12,700 XG)에서 두 번 50 ML 원뿔 튜브와 원심 분리기에 카세트. 각각의 원심 분리 단계 이후에 새로운 튜브에 뜨는을 붓고 펠렛을 폐기합니다. (40 분) </li><li> 건조 중량을 추정하여 피브로인의 농도를 측정한다. 무게 배에 실크 용액 1 ㎖를 붓고. 2 시간 동안 60 ℃의 오븐에서 샘플을 건조. 건조 실크 피브로인을 달아 실크 (100)에 의해 용액의 농도를 예상 얻어진 가중치를 곱하여 실크 피브로인 수용액의 농도를 계산하는 단계 6-9%이다 (W / V). </li><li> 증류수에 희석하여 (V / W)은 6 %로 실크 농도를 조정한다. 정류소 : 액체 실크 피브로인은 밀폐 용기에서 한 달 동안 4 ℃에서 저장 될 수있다. </li></ol></li><li> 실크 솔루션에서 다공성 지지체의 제조. <ol><li> 과립은 이후 단계에서 사용될 500-600 μm의, 크기가 별도의 NaCl을 과립 체. 과립 폐기S는 500 μm의 아래에 600 μm의 위의 크기. (15 분) </li><li> 폴리 테트라 플루오로 에틸렌 (PTFE) 금형 (도 1)로 6 % 실크 용액 30 ㎖를 붓는다. 부드럽게 실크 통해 체질의 NaCl 60g을 산란. 소금의 균일 한 층을 얻기 위해 용기를 누릅니다. 실크 중합 실온에서 48 시간을 품어. </li><li> 중합을 완료하고 남은 액체를 증발시켜 60 ℃에서 1 시간 동안 오븐에서 골격 함유 PTFE 금형을 배치. </li><li> 염을 걸러 48 시간 동안 증류수 2 L를 넣은 비커에 PTFE 몰드의 콘텐츠를 배치했다. 물을 하루에 2 ~ 3 시간을 변경합니다. . 염이 완전히 정지 시점 침출시 몰드로부터 스폰지 지지체를 제거 스폰지가 탈수 비계 않도록 밀폐 용기 내에서 39 ° C의 물에 침지하여 저장 될 수있다. </li><li> 준비가되면, 5mm 직경 생검 펀치와 비계를 잘라. 높이 약 2mm 도달하는 발판을 중고 컷. 푸2mm 직경 생검 펀치 (그림 2A)와 발판의 중심을 NCH. (1 시간) </li><li> . 정지 점 (습식주기 121 ° C, 20 분)들을 살균 물에 침지하여 지지체를 압력솥 ​​: 스폰지가 탈수 비계 않도록 밀폐 용기 내에서 39 ° C의 물에 침지하여 저장 될 수있다. </li><li> 계획된 세포 파종하기 전에, 멸균 0.1 ㎎ / ㎖ 폴리 -D- 라이신 (PDL) 솔루션의 발판을 담그지. 37 ℃에서 1 시간 동안 품어. </li><li> 비계가 결합되지 않은 PDL을 제거하는 인산염 완충 식염수 (PBS)로 3 배 씻으십시오. (30 분) </li></ol></li></ol> 쥐 두피 뉴런 2. 분리 <ol><li> 승인 동물 프로토콜을 수득 한 후 이전과 Pacifici Peruzzi (27)에 의해 기술 된 바와 같이 태아 일부터 18 (E18) 흰쥐 피질을 해부. (2 시간) </li><li> (3)에서 20 분 동안 (소 췌장)에서 0.3 %의 DNase I 0.25 % 트립신 5 ml의 10 피질을 부화7 ° C. </li><li> 1 ㎎ / ㎖ 대두 단백질의 동일한 양을 첨가함으로써 트립신을 비활성화한다. </li><li> 단일 세포 현탁액이 생성 될 때까지 최대 10 ㎖ 피펫 팅 파스퇴르 피펫을 사용하여 피질 아래로 20 번 씹다. 부드러운하고 기포 형성을 피할 것. (10 분) </li><li> 5 분 동안 127 XG에 세포 현탁액을 원심 분리기. </li><li> 다시 일시 배지 10ml에 세포 펠렛을 (로 Neurobasal 배지, 1X B27 보충제, 1X 루타, 1 % 페니실린 / 스트렙토 마이신). 세포를 계산합니다. 예상 세포 농도는 약 2 × 7 / ㎖이다. (20 분) </li></ol> 3. 조립 및 문화를 구축 <ol><li> 세포와 비계 파종. <ol><li> 세포 배양 후드 내부 살균 비계와 필요한 모든기구를 이동합니다. 사용 멸균 집게는 96 웰 세포 배양 플레이트에 웰 당 골격은 하나의 골격을 할당하는 배치. (10 분) </li><li> 그들 전에 종자를 셀에 평형화 세포 배양 배지에 담가 비계ING. 37 ℃에서 1 시간 동안 품어. (10 분) </li><li> 지지체로부터 매체의 과잉 대기음. </li><li> 세포 현탁액 / 비계의 100 μl를 적용합니다. (10 분) </li><li> 지지체에 세포 부착을 허용하도록 37 ° CO / N에서 세포를 품어. </li><li> 다음 아침에 비 부착 세포를 대기음 200 μL / 웰의 신선한 배양액을 적용합니다. (10 분) </li></ol></li><li> 콜라겐 매트릭스에 포함 비계. (2 시간) <ol><li> 나는 얼음에 콜라겐 10 배 PBS, 물, 1 N NaOH를 쥐 꼬리를 놓습니다. 제조업체의 지침에 따라 콜라겐의 작업 솔루션을 준비합니다. 셀 시드 구조 (1 시간까지) 준비가 될 때까지 얼음에 유지한다. </li><li> 인큐베이터에서 셀 시드 실크 구조를 제거하고 매체의 초과를 대기음. </li><li> 사용 멸균 집게는 잘 판에 빈 우물에 비계를 전송하고 3 ㎎ / ㎖ 콜라겐 용액 100 ㎕를 각 발판을 담그지. 다시 조직 배양 플레이트를 배치인큐베이터에서 30 분 콜라겐의 중합을 허용하는. </li><li> 웰 / 예열 세포 배양 배지 100 μl를 적용한다. 일주일 배양 배지의 절반 체적을 대체하여 매일 배지를 변경하기위한 구조. </li></ol></li></ol> 4. 현미경 분석 <ol><li> 라이브 / 죽은 염색 (1 시간) <ol><li> 요오드화 프로피 듐 (PI) 증류수에 1 ㎎ / ㎖ (1.5 밀리미터)의 주식 솔루션을 준비합니다. </li><li> 아세톤 플루 오레 디 아세테이트 (FDA) 2 ㎎ / ㎖의 주식 솔루션을 준비합니다. </li><li> PBS에 희석하여 10 μm의 파이 0.15 μm의 FDA를 포함하는 작업 솔루션을 준비합니다. 수욕 중에서 37 ℃까지 용액을 미리 가온. </li><li> 혈청 에스 테라 제를 제거하기 위해 미리 예열 PBS로 세포를 씻으십시오. PBS를 대기음. </li><li> 2 분 동안 세포에 미리 예열 작업 솔루션을 적용하고 PBS로 씻어. </li><li> FDA 전 λ = 490 N; 이미지에 epifluorescent 현미경을 사용하여 세포 (PI의 전 λ = 490 nm의은, EM λ는 570 nm의 =m은, EM λ)는 514 nm의 =. 얼룩은 40 분에 걸쳐 안정적으로 유지. 장시간 염색 PI의 세포에 의한 흡수와 세포에서 PI / FDA의 공동 지방화에 따른 불특정 오염의 원인이 될 수 있습니다. </li></ol></li><li> 면역 염색 <ol><li> 배양 중 원하는 시점에서 RT에서 30 분 동안 4 % 파라 포름 알데히드 (PFA)으로 세포를 고정한다. 인해 PFA의 독성에 고정하는 단계는 화학 퓸 후드에서 수행되어야 발연. </li><li> . 배 PBS 중지 포인트 발판을 씻으 : PFA 고정 구조는 추가 단계를 진행하기 전에 며칠 동안 4 ° C에서 PBS에 저장 될 수있다. </li><li> 4 ℃에서 일차 항체 O / N을 함유하는 PBS에서 0.2 % 트리톤, 0.25 % 소 혈청 알부민 (BSA)의 골격을 부화. </li><li> 다음 날은 염색 액을 버리고 언 바운드 차 항체를 제거하는 PBS로 골격을 3 × 30 분을 씻는다. </li><li> 2 PBS에 트리톤 0.2 %에 희석 차 항체, 0.25 % BSA로 샘플을 품어실온에서 시간. </li><li> 염색 액을 제거하고 언 바운드 차 항체를 제거하는 PBS로 골격을 3 × 30 분을 씻는다. </li><li> 이미지 1 μm의 단계로 샘플의 100 μm의 Z-부분을 고려하여 20 배 목표와 공 초점 현미경을 사용하여 비계. 이미지 해상도가 최소 1,024 X 1,024 픽셀이어야 얇은 신경 돌기를 시각화합니다. </li></ol></li><li> RNA, DNA와 단백질 분리 주 : RNA, DNA 및 단백질 분리는 제조자의 지시에 따라 상용 AllPrep DNA / RNA / 단백질 미니 키트를 사용하여 수행된다. <ol><li> 사용 멸균 집게는 2 ml의 멸균 튜브에 문화 판에서 발판을 전송합니다. 튜브 당 하나의 발판을 놓습니다. </li><li> 각각의 튜브에 RLT 버퍼의 200 μl를 추가합니다. </li><li> 멸균 microscissors로 세분화하여 구조를 방해. </li><li> 분열 조직을 균일화하려면, 스핀 컬럼 튜브의 콘텐츠를 전송. 마이크로 원심에서 최고 속도로 2 분 동안 스핀.이 스핀 컬럼을 통과 할 해물 균질화된다. </li><li> 을 통해 흐름을 수집하고 RNA, 제조 업체 프로토콜 다음 DNA와 단백질을 분리하는 즉시 사용할 수 있습니다. </li><li> 핵산의 수율 호환되는 다른 방법 (예를 들면, NanoDrop)을 정량화. </li><li> 제조업체의 지시에 따라 BCA 단백질 분석을 이용하여 단백질을 정량 수율. 파장 562 nm에서 마이크로 플레이트 리더를 사용하여 분석의 결과를 측정한다. 주 : 핵산 및 세포 밀도와 관련 구조체 당 단백질의 예상 수율은도 4에 도시된다. </li></ol></li></ol>

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이 비디오 문서의 공개는 코닝 후원됩니다.

Here we described the guidelines to assemble a compartmentalized 3D brain-like tissue model. The model is characterized by dense polarized culture of neurons resulting in the development of two morphologically different compartments: one containing densely packed cell bodies, second containing pure axonal networks. Overall, the scaffold architecture and growth pattern mimic brain cortical tissue including the six laminar layers and white matter tracts21.
The donut-shaped silk protein-based tissue model allows for modifications and tuning of mechanical properties, versatile structural forms, hydrogel fillers and cellular components. Thus, this tissue model establishes a base platform for a wide range of studies. Silk is a favorable candidate for biomaterial platforms due to its biocompatibility, aqueous-based processing, and robust mechanical and degradation properties22. The silk matrix also serves as a stable anchor to reduce collagen gel contraction over time in culture. The properties such as silk concentration and porosity of the scaffold used in this model have been previously adjusted to achieve optimal cell growth and mechanical properties resulting in brain-like tissue elasticity18,23,24. We suggest to keep these parameters constant to ensure the successful outcome and reproducibility of the experiments.
The 3D neuronal network formation was achieved by combining two types of biomaterials with different mechanical properties: a stiff scaffold to provide neuronal anchoring and a softer gel matrix to permit axon penetration and connectivity in 3D. Selective material preferences of the silk scaffold and soft hydrogel provide the underlying principle for compartmentalizing the neurons from the axonal connections. Due to the inert nature of the silk scaffold, functionalization with poly-D-lysine is required for neuronal attachment. However, other cell adhesion promoting factors can be applied such as RGD25 or fibronectin26. To achieve the 3D network formation the silk scaffold needs to be filled with hydrogel in a timely manner as soon as neurons are attached to the scaffold. Likewise, the collagen matrix filler can be replaced by other hydrogels, thus allowing the study of the influence of 3D extracellular environments on axonal network formation to serve as a platform to evaluate novel hydrogels in terms of neuronal compatibility. Additionally, apart from rat cortical neurons other neuronal sources such as hippocampal neurons or induced pluripotent cell (iPSc)-derived neurons can be utilized. Moreover, the tissue model can be used to study heterocellular interactions by including glial cells along with neurons and to build more complex brain-like tissue.
As shown previously, our model can be utilized to evaluate neuronal functionality in 3D microenvironment with a variety of assays such as cell viability, gene expression, LC-MS/MS and electrophysiology, thus demonstrating physiological relevance of the model18. Other methods, which are frequently utilized to evaluate 3D tissue-engineered constructs, such as immunostaining and microscopy8,9,11 can also be used to assess cell distribution and extent of axonal network formation. However, it has to be noted, that due to the high density of the collagen matrix, the penetration of antibodies and depth of the imaging is limited to few hundred micrometers. Moreover, the signal to noise ratio may be affected by nonspecific background fluorescence. This can be overcome by using lipophilic cell tracers and genetically expressed fluorescent proteins which diminish the need for immunostaining11. Alternatively, the imaging can be performed with 2-photon microscopy instead of usual one-photon technique, which may reduce the signal loss, photobleaching, and can be extended to several hundred micrometers of depth.
Summarizing, the silk and collagen-based brain-like tissue offers a robust platform to study neuronal networks in 3D and is a starting point for the development of more advanced models of neurological disorders in the future. Independent from the mode of evaluation, the relative simplicity of this tissue model supports its utility, success and reproducibility.

중추 신경계 (CNS)의 구조적 기능적, 감염성 또는 퇴행성 혈관을 포함하는 다양한 질환에 의해 영향을받을 수있다. 추정 6백80만명 1은 전 세계적으로 성장하고 사회 경제적 부담을 나타내는 신경 질환의 결과로 매년 죽는다. 그러나, 장애의 몇 가지 가능한 치료를해야합니다. 따라서, 신경계 질환을 앓고있는 환자를위한 치료 전략의 혁신적인 중요한 필요성이있다. 불행히도, 많은 CNS 타겟 치료제 인해 생리 학적으로 관련 기능 판독과 급성 및 만성 영향 평가를 허용하지 않는 부적절한 전임상 연구 모델의 활용에 부분적으로 임상 시험 중에 실패합니다. 지난 수십 년간 상당한 연구 노력에도 불구하고, CNS의 구조와 기능에 대해 알 수없는 방대한있다. 더 많은 지식을 습득하기 위하여, 동물 모델은 종종 우리 아르ED 특히 전임상 연구에서, 이러한 외상성 뇌 손상 (TBI), 또는 치매 병리 상태를 모델링한다. 그러나 동물은 인간에서 모두 중추 신경계의 해부학에서뿐만 아니라, 기능, 유전자 발현 및 대사 2-4에 유의 한 차이. 한편, 2D 체외 배양 세포 생물학을 연구하는 일반적인 방법이고 정기적 약물 발견에 사용된다. 그러나, 2 차원 세포 배양은 복잡하고 인간의 두뇌 5-7에 비해 생체 적합성이 부족하다. 저가 및 단순성 2D 세포 배양 연구 또는 동물 모델에 의해 제공되는 복잡성을 대신 없지만, 3 차원의 조직 공학은 시험 관내 및 생체 내 접근법에서 2D 사이에 존재하는 간극을 폐쇄 개선 연구 모델을 생성 할 수있다. 3 차원의 조직 공학은 3D 세포 - 세포 상호 작용에 의해 제공되는 지지체 생체 외 단서에 의해 달성 이상의 생리 학적으로 관련 실험 조건을 제공한다. Desp3D 배양 값 뒤에 상당한 증거 ITE, 거기 이러한 줄기 세포 유래 organoid 배양 8-10 같은 몇 3D CNS 조직 모델 11 neurospheroids는 현재 및 하이드로 겔 배양 12,13 분산. 다층 리소그래피 (14), 및 3D 인쇄 (15) 등의 고급 기술 방법은 폐, 간 및 신장 조직을 연구에 이용되어왔다. 그러나, 대뇌 피질의 구조 생물학을 흉내 낸으로 구획 된 신경 세포의 성장을 허용 3D CNS 모델의 부족이있다. 신경 세포 기관에서 신경 돌기의 분리 된 성장은 이전 축삭 기관의 추적, 칼슘 유입, 네트워크 아키텍처 및 활동의 연구를 허용 미세 (16, 17)를 사용하여 2D 문화에서 증명되었다. 이 아이디어는 세포체와 축삭 책자는 뇌 (18)의 계층 구조를 흉내 낸 다른 구획에있는 3D 편광 신경 조직을 개발하기 위해 우리에게 영감을 </sup&gt;. 우리의 접근은 제한된 용적의 셀을 고밀도로 수용하고 콜라겐 겔에 치밀한 축삭 네트워크의 생장을 허용 고유 실크 골격 설계의 사용에 기초한다. 여기에서 우리는 인공 지지체 제조 및 신경 세포 배양을 포함한 뇌와 같은 조직의 전체 조립 과정을 보여줍니다.

<table><tbody><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>223530</td><td></td></tr><tr><td>LiBr</td><td>Sigma-Aldrich</td><td>213225</td><td></td></tr><tr><td>MWCO 3500 dialysis cassettes&amp;nbsp;</td><td>Thermo Fisher</td><td>66110</td><td></td></tr><tr><td>Heating plate</td><td>Fisher Scientific</td><td>Isotemp</td><td></td></tr><tr><td>Centrifuge 5804 R</td><td>Eppendorf</td><td></td><td></td></tr><tr><td>Sieve</td><td>Fisher Scientific</td><td></td><td>No. 270, No. 35, No. 30</td></tr><tr><td>PTFE mold</td><td></td><td></td><td>made in house (&lt;strong&gt;Figure 1&lt;/strong&gt;) 10 cm diameter, 2 cm height</td></tr><tr><td>NaCl</td><td>Sigma-Aldrich</td><td>71382</td><td></td></tr><tr><td>Biopsy Punch 5&amp;#160;mm</td><td>World Precision Instrument</td><td>501909</td><td></td></tr><tr><td>Biopsy Punch 2&amp;#160;mm</td><td>World Precision Instrument</td><td>501908</td><td></td></tr><tr><td>poly-D-lysine</td><td>Sigma-Aldrich</td><td>P6407-5MG</td><td>final concentration 10&amp;#160;&amp;#956;g/ml, dissolved in water</td></tr><tr><td>PBS</td><td>Sigma-Aldrich</td><td>D1283-500ML</td><td></td></tr><tr><td>Trypsin</td><td>Sigma-Aldrich</td><td>T4049-500ML</td><td></td></tr><tr><td>DNase</td><td>Roche</td><td>10104159001</td><td>final concentration 0.3%</td></tr><tr><td>Soybean protein</td><td>Sigma-Aldrich</td><td>T6522-100MG</td><td>final concentration 1&amp;#160;mg/ml</td></tr><tr><td>Neurobasal medium</td><td>Gibco</td><td>21103049</td><td>warm up to 37&amp;#160;&amp;deg;C before use</td></tr><tr><td>B27 supplement 50x</td><td>Gibco</td><td>17504-044</td><td></td></tr><tr><td>Glutamax</td><td>Gibco</td><td>35050-061</td><td></td></tr><tr><td>Penicilin Streptomycin</td><td>Corning</td><td>30-002-CI</td><td></td></tr><tr><td>Collagen I, rat tail, 100&amp;#160;mg</td><td>Corning</td><td>354236</td><td>final concentration 3&amp;#160;mg/ml</td></tr><tr><td>NaOH</td><td>Sigma-Aldrich</td><td>S2770</td><td>corrosive</td></tr><tr><td>Propidium Iodide</td><td>Sigma-Aldrich</td><td>P4170-10MG</td><td>toxic</td></tr><tr><td>Fluorescein Diacetate</td><td>Sigma-Aldrich</td><td>F7378-5G</td><td></td></tr><tr><td>Olympus MVX10</td><td>Olympus</td><td></td><td></td></tr><tr><td>Paraformaldehyde</td><td>Sigma-Aldrich</td><td>P6148</td><td>toxic, final concentration 4%</td></tr><tr><td>Bovine Serum Albumin</td><td>Sigma-Aldrich</td><td>A7906-10G</td><td></td></tr><tr><td>anti-&amp;beta;IIITubulin antibody&amp;nbsp;</td><td>Sigma-Aldrich</td><td>T2200</td><td>rabbit 1:500</td></tr><tr><td>anti-rabbit Alexa-546</td><td>Molecular Probes</td><td>A11010</td><td>goat 1:250</td></tr><tr><td>goat serum</td><td>Sigma-Aldrich</td><td>G9023-5ML</td><td></td></tr><tr><td>Leica SP2 confocal microscope</td><td>Leica</td><td></td><td>objective 20X</td></tr><tr><td>QIAshredder</td><td>Qiagen</td><td>79654</td><td></td></tr><tr><td>AllPrep DNA/RNA/Protein Mini Kit</td><td>Qiagen</td><td>80004</td><td></td></tr><tr><td>Ethyl alcohol, Pure</td><td>Sigma-Aldrich</td><td>E7023&amp;nbsp;</td><td></td></tr><tr><td>2-Mercaptoethanol</td><td>Sigma-Aldrich</td><td>63689</td><td></td></tr><tr><td>NanoDrop 2000c/2000 UV-Vis Spectrophotometer</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>BCA protein assay</td><td>Thermo Scientific</td><td>23225</td><td></td></tr><tr><td>Plate reader Spectramax M2</td><td>Molecular Devices</td><td></td><td>absorbance 562 nm</td></tr><tr><td>Micro Scissors, Economy, Vannas-type</td><td>TedPella</td><td>1346</td><td></td></tr></tbody></table>

engineered 3d silk-collagen-based model of polarized neural tissue

Despite huge efforts to decipher the anatomy, composition and function of the brain, it remains the least understood organ of the human body. To gain a deeper comprehension of the neural system scientists aim to simplistically reconstruct the tissue by assembling it in vitro from basic building blocks using a tissue engineering approach. Our group developed a tissue-engineered silk and collagen-based 3D brain-like model resembling the white and gray matter of the cortex. The model consists of silk porous sponge, which is pre-seeded with rat brain-derived neurons, immersed in soft collagen matrix. Polarized neuronal outgrowth and network formation is observed with separate axonal and cell body localization. This compartmental architecture allows for the unique development of niches mimicking native neural tissue, thus enabling research on neuronal network assembly, axonal guidance, cell-cell and cell-matrix interactions and electrical functions.

도넛 모양 솔리드 실크 스폰지 미리 절단은 신경 조직 (그림 2A)를 닮은 구획 구조를 달성하기 위해 독특하고 간단한 아이디어를 나타냅니다. 작은 부피 내에 시드 및 높은 세포 밀도의 증가를 허용하는 매우 높은 표면적이 약 500 μm의 결과 공경 지지체의 다공성 구조 (2 × 7 / ㎖) (도 2B). 또한, 발판의 높은 다공성 연장 시간 프레임을 통해 고밀도 세포 배양의 뛰어난 생존 능력의 결과로 영양분과 폐기물의 무제한 확산 수 있습니다. 신경 세포를 파종시 신속하고 균일하게 발판 기공의 표면에 부착합니다. 세포 부착이 완료되고 세포 실크 기판 상에 평형화 된 후, 스폰지 지지체가 축삭 네트워크 형성 (도 3 차원 환경을 제공하기 위해 부드러운 콜라겐 매트릭스로 채워진다 </strong&gt;). 뉴런은 단지 2 차원 표면 (도 3b)와 혼합 발견 네트워크 결과 기공의 표면에 확장을 성장 콜라겐 매트릭스의 부재 축삭과 세포체의 구획화는 불가능하다. 반면에, 콜라겐 젤은 신경 세포 기관이 실크 발판 (그림 3C)에 부착 된 상태로 유지하면서, 3D 광범위한 축삭 가지를 지원하는 메쉬 작업을 제공합니다. 이러한 성장 패턴은 세포 기관과 순수 축삭 네트워크 뇌의 피질의 회색과 흰색 물질과 유사합니다 (그림 3D)의 구획화에 연결됩니다. 그렇다 현미경에서, 구조물은 실험 뒤에 질문에 따라, 다른 방법 (18)의 다양한 평가 될 수있다. 예를 들어, 구조물에서 DNA, RNA 및 단백질의 분리가 용이하게 상업적 키트를 (도 4)을 사용하여 수행 할 수있다. 핵산 및 단백질 PE의 수율R 구조체는 초기에 실크 비계에 시드 셀의 개수에 의존한다. 이상의 셀 시드 DNA, RNA 및 단백질의 높은 수율. <img alt="그림 1" src="/files/ftp_upload/52970/52970fig1.jpg" /> 실크 스폰지 지지체의 제조에 사용 그림 1. PTFE 금형 크기 :.. 10cm 직경 2cm 높이 <a href="https://www.jove.com/files/ftp_upload/52970/52970fig1large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> <img alt="그림 2" src="/files/ftp_upload/52970/52970fig2.jpg" /> 그림 2. 3D 뇌와 같은 조직 모델입니다. (A) 다공성 실크 스폰지 발판. 전에 콜라겐 (녹색 살아있는 세포, 붉은 죽은 세포)를 포함 실크 인공 지지체에 파종에 따라 1 일에서 신경 세포의 (B) 라이브 / 죽은 얼룩. 오른쪽 패널은 엄마를 표시빨간색 프레임에서 캡처 영역의 gnification. <a href="https://www.jove.com/files/ftp_upload/52970/52970fig2large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> <img alt="그림 3" src="/files/ftp_upload/52970/52970fig3.jpg" /> 그림 3. 신경 세포의 3 차원 뇌와 같은 조직 모델에서 구획 가지 (A) 비계 구획 :. 레드 셀 바디 컴, 블루 축삭 함. (B) 콜라겐 삽입 전에 파종에 따라 1 일에서 신경 세포의 성장 패턴. (C). 세포체 구획 씨딩 7 일에 신경 생장. (D) 축삭 구획에 파종시 7 일에 신경 가지. 녹색 -. βIIITubulin <a href="https://www.jove.com/files/ftp_upload/52970/52970fig3large.jpg" target="_blank">이의 더 큰 버전을 보려면 여기를 클릭하십시오</a>그림. <img alt="그림 4" src="/files/ftp_upload/52970/52970fig4.jpg" /> (A) RNA와 DNA, 그리고 발판 당 시드 세포의 양에 관련 구조 당 (B) 단백질의 그림 4. 예상 수율 (± 표준 편차, N = 5). <a href="https://www.jove.com/files/ftp_upload/52970/52970fig4large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오 .</a>

Watch this Scientific Journal Video about Engineered 3D Silk-collagen-based Model of Polarized Neural Tissue at JoVE.com

Engineered 3D Silk-collagen-based Model of Polarized Neural Tissue

Insight into the complex actions of the brain requires advanced research tools. Here we demonstrate a novel silk-collagen-based 3D engineered model of neural tissue resembling brain-like architecture. The model can be used to study neuronal network assembly, axonal guidance, cell-cell interactions and electrical activity.

편광 신경 조직의 엔지니어링 3D 실크 콜라겐 기반 모델

Despite huge efforts to decipher the anatomy, composition and function of the brain, it remains the least understood organ of the human body. To gain a ...

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JoVE Journal

Bioengineering

12.4K 조회수.  Tufts University. Insight into the complex actions of the brain requires advanced research tools. Here we demonstrate a novel silk-collagen-based 3D engineered model of neural tissue resembling brain-like architecture. The model can be used to study neuronal network assembly, axonal guidance, cell-cell interactions and electrical activity.

비디오: Engineered 3D Silk-collagen-based Model of Polarized Neural Tissue

Three-Dimensional In Vitro Biomimetic Model of Neuroblastoma Using Collagen-Based Scaffolds

Neuroblastoma is the most common extracranial solid tumor in children, accounting for 15% of overall pediatric cancer deaths. The native tumor tissue is a complex three-dimensional (3D) microenvironment involving layers of cancerous and non-cancerous cells surrounded by an extracellular matrix (ECM). The ECM provides physical and biological support and contributes to disease progression, patient prognosis, and therapeutic response.
This paper describes a protocol for assembling a 3D scaffold-based system to mimic the neuroblastoma microenvironment using neuroblastoma cell lines and collagen-based scaffolds. The scaffolds are supplemented with either nanohydroxyapatite (nHA) or glycosaminoglycans (GAGs), naturally found at high concentrations in the bone and bone marrow, the most common metastatic sites of neuroblastoma. The 3D porous structure of these scaffolds allows neuroblastoma cell attachment, proliferation and migration, and the formation of cell clusters. In this 3D matrix, the cell response to therapeutics is more reflective of the in vivo situation.
The scaffold-based culture system can maintain higher cell densities than conventional two-dimensional (2D) cell culture. Therefore, optimization protocols for initial seeding cell numbers are dependent on the desired experimental timeframes. The model is monitored by assessing cell growth via DNA quantification, cell viability via metabolic assays, and cell distribution within the scaffolds via histological staining.
This model&#39;s applications include the assessment of gene and protein expression profiles as well as cytotoxicity testing using conventional drugs and miRNAs. The 3D culture system allows for the precise manipulation of cell and ECM components, creating an environment more physiologically similar to native tumor tissue. Therefore, this 3D in vitro model will advance the understanding of the disease pathogenesis and improve the correlation between results obtained in vitro, in vivo in&#160;animal models, and human subjects.

Three-Dimensional In Vitro Biomimetic Model of Neuroblastoma Using Collagen-Based Scaffolds

This paper lists the steps required to seed neuroblastoma cell lines on previously described three-dimensional collagen-based scaffolds, maintain cell growth for a predetermined timeframe, and retrieve scaffolds for several cell growth and cell behavior analyses and downstream applications, adaptable to satisfy a range of experimental aims.

콜라겐 기반 스캐폴드를 사용한 신경모세포종의 3차원 체외 생체모방 모델

Neuroblastoma is the most common extracranial solid tumor in children, accounting for 15% of overall pediatric cancer deaths. The native tumor tissue is a ...

연구

암 연구학

Three-dimensional Tissue Engineered Aligned Astrocyte Networks to Recapitulate Developmental Mechanisms and Facilitate Nervous System Regeneration

Neurotrauma and neurodegenerative disease often result in lasting neurological deficits due to the limited capacity of the central nervous system (CNS) to replace lost neurons and regenerate axonal pathways. However, during nervous system development, neuronal migration and axonal extension often occur along pathways formed by other cells, referred to as &#34;living scaffolds&#34;. Seeking to emulate these mechanisms and to design a strategy that circumvents the inhibitory environment of the CNS, this manuscript presents a protocol to fabricate tissue engineered astrocyte-based &#34;living scaffolds&#34;. To create these constructs, we employed a novel biomaterial encasement scheme to induce astrocytes to self-assemble into dense three-dimensional bundles of bipolar longitudinally-aligned somata and processes. First, hollow hydrogel micro-columns were assembled, and the inner lumen was coated with collagen extracellular-matrix. Dissociated cerebral cortical astrocytes were then delivered into the lumen of the cylindrical micro-column and, at a critical inner diameter of &#60;350 &#181;m, spontaneously self-aligned and contracted to produce long fiber-like cables consisting of dense bundles of astrocyte processes and collagen fibrils measuring &#60;150 &#181;m in diameter yet extending several cm in length. These engineered living scaffolds exhibited &#62;97% cell viability and were virtually exclusively comprised of astrocytes expressing a combination of the intermediate filament proteins glial-fibrillary acidic protein (GFAP), vimentin, and nestin. These aligned astrocyte networks were found to provide a permissive substrate for neuronal attachment and aligned neurite extension. Moreover, these constructs maintain integrity and alignment when extracted from the hydrogel encasement, making them suitable for CNS implantation. These preformed constructs structurally emulate key cytoarchitectural elements of naturally occurring glial-based &#34;living scaffolds&#34; in vivo. As such, these engineered living scaffolds may serve as test-beds to study neurodevelopmental mechanisms in vitro or facilitate neuroregeneration by directing neuronal migration and/or axonal pathfinding following CNS degeneration in vivo.

We showcase the development of self-assembled, three-dimensional bundles of longitudinally aligned astrocytic somata and processes within a novel biomaterial encasement. These engineered &#34;living scaffolds&#34;, exhibiting micron-scale diameter yet extending centimeters in length, may serve as test-beds to study neurodevelopmental mechanisms or facilitate neuroregeneration by directing neuronal migration and/or axonal pathfinding.

3 차원 조직 설계 정렬 사이토 네트워크 발달 메커니즘을 정리 하 고 신경 재생을 촉진 하

Neurotrauma and neurodegenerative disease often result in lasting neurological deficits due to the limited capacity of the central nervous system (CNS) to ...

생체공학

Interfacing 3D Engineered Neuronal Cultures to Micro-Electrode Arrays: An Innovative In Vitro Experimental Model

Currently, large-scale networks derived from dissociated neurons growing and developing in vitro on extracellular micro-transducer devices are the gold-standard experimental model to study basic neurophysiological mechanisms involved in the formation and maintenance of neuronal cell assemblies. However, in vitro studies have been limited to the recording of the electrophysiological activity generated by bi-dimensional (2D) neural networks. Nonetheless, given the intricate relationship between structure and dynamics, a significant improvement is necessary to investigate the formation and the developing dynamics of three-dimensional (3D) networks. In this work, a novel experimental platform in which 3D hippocampal or cortical networks are coupled to planar Micro-Electrode Arrays (MEAs) is presented. 3D networks are realized by seeding neurons in a scaffold constituted of glass microbeads (30-40 &#181;m in diameter) on which neurons are able to grow and form complex interconnected 3D assemblies. In this way, it is possible to design engineered 3D networks made up of 5-8 layers with an expected final cell density. The increasing complexity in the morphological organization of the 3D assembly induces an enhancement of the electrophysiological patterns displayed by this type of networks. Compared with the standard 2D networks, where highly stereotyped bursting activity emerges, the 3D structure alters the bursting activity in terms of duration and frequency, as well as it allows observation of more random spiking activity. In this sense, the developed 3D model more closely resembles in vivo neural networks.

Interfacing 3D Engineered Neuronal Cultures to Micro-Electrode Arrays: An Innovative In Vitro Experimental Model

In this work, a novel experimental model in which 3D neuronal cultures are coupled to planar Micro-Electrode Arrays (MEAs) is presented. 3D networks are built by seeding neurons in a scaffold made up of glass microbeads on which neurons grow and form interconnected 3D structures.

마이크로 전극 배열에 3D 엔지니어링의 연결을 문화의 인터페이스 : 혁신을<em&gt; 체외</em&gt; 실험 모델

Currently, large-scale networks derived from dissociated neurons growing and developing in vitro on extracellular micro-transducer devices are the ...

신경과학

Anatomically Inspired Three-dimensional Micro-tissue Engineered Neural Networks for Nervous System Reconstruction, Modulation, and Modeling

Functional recovery rarely occurs&#160;following injury or disease-induced degeneration within the central nervous system (CNS)&#160;due to the inhibitory environment and the limited capacity for neurogenesis. We are developing&#160;a strategy to simultaneously address&#160;neuronal and axonal pathway loss within the damaged CNS. This manuscript presents the fabrication protocol for micro-tissue engineered neural networks (micro-TENNs), implantable constructs consisting of neurons and aligned axonal tracts spanning the extracellular matrix (ECM) lumen of a preformed hydrogel cylinder hundreds of microns in diameter that may extend centimeters in length. Neuronal aggregates are delimited to the extremes of the three-dimensional encasement and are spanned by axonal projections. Micro-TENNs are uniquely poised as a strategy for CNS reconstruction, emulating aspects of brain connectome cytoarchitecture and potentially providing means for network replacement. The neuronal aggregates may synapse with host tissue to form new functional relays to restore and/or modulate missing or damaged circuitry. These constructs may also act as pro-regenerative&#160;&#34;living scaffolds&#34; capable of exploiting developmental mechanisms for cell migration and axonal pathfinding, providing synergistic structural and soluble cues based on the state of regeneration. Micro-TENNs are fabricated by pouring liquid hydrogel into a cylindrical mold containing a longitudinally centered needle. Once the hydrogel has gelled, the needle is removed, leaving a hollow micro-column. An ECM solution is added to the lumen to provide an environment suitable for neuronal adhesion and axonal outgrowth. Dissociated neurons are mechanically aggregated for precise seeding within one or both ends of the micro-column. This methodology reliably produces self-contained miniature constructs with long-projecting axonal tracts that may recapitulate features of brain neuroanatomy. Synaptic immunolabeling and genetically encoded calcium indicators suggest that micro-TENNs possess extensive synaptic distribution and intrinsic electrical activity. Consequently, micro-TENNs represent a promising strategy for targeted neurosurgical reconstruction of brain pathways and may also be applied as biofidelic models to study neurobiological phenomena in vitro.

This manuscript details the fabrication of micro-tissue engineered neural networks: three-dimensional micron-sized constructs comprised of long aligned axonal tracts spanning aggregated neuronal population(s) encased in a tubular hydrogel. These living scaffolds can serve as functional relays to reconstruct or modulate neural circuitry or as biofidelic test-beds mimicking gray-white matter neuroanatomy.

신경 시스템 재구성, 변조 및 모델링을 위해 해부학 적으로 영감을받은 3 차원 미세 조직 공학 신경 회로망

Functional recovery rarely occurs&#160;following injury or disease-induced degeneration within the central nervous system (CNS)&#160;due to the inhibitory ...

Generation of 3-D Collagen-based Hydrogels to Analyze Axonal Growth and Behavior During Nervous System Development

This protocol uses natural type I collagen to generate three-dimensional (3-D) hydrogel for monitoring and analyzing the axonal growth. The protocol is centered on culturing small pieces of embryonic or early postnatal rodent brains inside a 3-D hydrogel formed by the rat tail tendon-derived type I collagen with specific porosity. Tissue pieces are cultured inside the hydrogel and confronted to specific brain fragments or genetically-modified cell aggregates to produce and secrete molecules suitable for creating a gradient inside the porous matrix. The steps of this protocol are simple and reproducible but include critical steps to be considered carefully during its development. Moreover, the behavior of growing axons can be monitored and analyzed directly using a phase-contrast microscope or mono/multiphoton fluorescence microscope after fixation by immunocytochemical methods.

Here, we provide a method for analyzing the behavior of growing axons in 3D matrices, mimicking their natural development.

신경계 발달 중 축산 성장과 행동을 분석하는 3-D 콜라겐 기반 하이드로겔 생성

This protocol uses natural type I collagen to generate three-dimensional (3-D) hydrogel for monitoring and analyzing the axonal growth. The protocol is ...

Microgel-Extracellular Matrix Composite Support for the Embedded 3D Printing of Human Neural Constructs

The embedded 3D printing of cells inside a granular support medium has emerged in the past decade as a powerful approach for the freeform biofabrication of soft tissue constructs. However, granular gel formulations have been restricted to a limited number of biomaterials that allow for the cost-effective generation of large amounts of hydrogel microparticles. Therefore, granular gel support media have generally lacked the cell-adhesive and cell-instructive functions found in the native extracellular matrix (ECM).
To address this, a methodology has been developed for the generation of self-healing annealable particle-extracellular matrix (SHAPE) composites. SHAPE composites consist of a granular phase (microgels) and a continuous phase (viscous ECM solution) that, together, allow for both programmable high-fidelity printing and an adjustable biofunctional extracellular environment. This work describes how the developed methodology can be utilized for the precise biofabrication of human neural constructs.
First, alginate microparticles, which serve as the granular component in the SHAPE composites, are fabricated and combined with a collagen-based continuous component. Then, human neural stem cells are printed inside the support material, followed by the annealing of the support. The printed constructs can be maintained for weeks to allow the differentiation of the printed cells into neurons. Simultaneously, the collagen continuous phase allows for axonal outgrowth and the interconnection of regions. Finally, this works provides information on how to perform live-cell fluorescence imaging and immunocytochemistry to characterize the 3D-printed human neural constructs.

This work describes a protocol for the freeform embedded 3D printing of neural stem cells inside self-healing annealable particle-extracellular matrix composites. The protocol enables the programmable patterning of interconnected human neural tissue constructs with high fidelity.

인간 신경 구조물의 임베디드 3D 프린팅을 위한 마이크로겔-세포외 기질 복합체 지원

The embedded 3D printing of cells inside a granular support medium has emerged in the past decade as a powerful approach for the freeform biofabrication ...

iPSC 유래 뉴런 및 성상세포의 3D 바이오프린팅 공동 배양

Three-Dimensional Bioprinting of Human iPSC-Derived Neuron-Astrocyte Cocultures for Screening Applications

For a cell model to be viable for drug screening, the system must meet throughput and homogeneity requirements alongside having an efficient development time. However, many published 3D models&#160;do not satisfy these criteria. This therefore, limits their usefulness in early drug discovery applications. Three-dimensional (3D) bioprinting is a novel technology that can be applied to the development of 3D models to expedite development time, increase standardization, and increase throughput. Here, we present a protocol to develop 3D bioprinted coculture models of human induced pluripotent stem cell (iPSC)-derived glutamatergic neurons and astrocytes. These cocultures are embedded within a hydrogel matrix of bioactive peptides, full-length extracellular matrix (ECM) proteins, and with a physiological stiffness of 1.1 kPa. The model can be rapidly established in 96-well and 384-well formats and produces an average post-print viability of 72%. The astrocyte-to-neuron ratio in this model is shown to be 1:1.5, which is within the physiological range for the human brain. These 3D bioprinted cell populations also show expression of mature neural cell type markers and growth of neurite and astrocyte projections within 7 days of culture. As a result, this model is suitable for analysis using cell dyes and immunostaining techniques alongside neurite outgrowth assays. The ability to produce these physiologically representative models at scale makes them ideal for use in medium-to-high throughput screening assays for neuroscience targets.

저자 스포트라이트: 3D 세포 모델링의 발전 – 신경 공배양을 위한 고처리량 접근 방식 

Here, we present a protocol to produce 3D-bioprinted cocultures of iPSC-derived neurons and astrocytes. This coculture model, generated within a hydrogel scaffold in 96- or 384-well formats, demonstrates high post-print viability and neurite outgrowth within 7 days and shows the expression of maturity markers for both cell types.

스크리닝 응용 분야를 위한 인간 iPSC 유래 뉴런-성상세포 공동 배양의 3차원 바이오프린팅

For a cell model to be viable for drug screening, the system must meet throughput and homogeneity requirements alongside having an efficient development ...

마이크로 스케일 신경 세포 배양 장치를 위한 3D 프린팅의 응용

Two-Photon Polymerization 3D-Printing of Micro-scale Neuronal Cell Culture Devices

Neuronal cultures have been a reference experimental model for several decades. However, 3D cell arrangement, spatial constraints on neurite outgrowth, and realistic synaptic connectivity are missing. The latter limits the study of structure and function in the context of compartmentalization and diminishes the significance of cultures in neuroscience. Approximating ex vivo the structured anatomical arrangement of synaptic connectivity is not trivial, despite being key for the emergence of rhythms, synaptic plasticity, and ultimately, brain pathophysiology. Here, two-photon polymerization (2PP) is employed as a 3D printing technique, enabling the rapid fabrication of polymeric cell culture devices using polydimethyl-siloxane (PDMS) at the micrometer scale. Compared to conventional replica molding techniques based on microphotolitography, 2PP micro-scale printing enables rapid and affordable turnaround of prototypes. This protocol illustrates the design and fabrication of PDMS-based microfluidic devices aimed at culturing modular neuronal networks. As a proof-of-principle, a two-chamber device is presented to physically constrain connectivity. Specifically, an asymmetric axonal outgrowth during ex vivo development is favored and allowed to be directed from one chamber to the other. In order to probe the functional consequences of unidirectional synaptic interactions, commercial microelectrode arrays are chosen to monitor the bioelectrical activity of interconnected neuronal modules. Here, methods to 1) fabricate molds with micrometer precision and 2) perform in vitro multisite extracellular recordings in rat cortical neuronal cultures are illustrated. By decreasing costs and future widespread accessibility of 2PP 3D-printing, this method will become more and more relevant across research labs worldwide. Especially in neurotechnology and high-throughput neural data recording, the ease and rapidity of prototyping simplified in vitro models will improve experimental control and theoretical understanding of in vivo large-scale neural systems.

저자 스포트라이트: 뇌 기능 분석을 위한 모듈식 뉴런 네트워크

3D printing at the micrometer scale enables rapid prototyping of polymeric devices for neuronal cell cultures. As a proof-of-principle, structural connections between neurons were constrained by creating barriers and channels influencing neurite outgrowth, while the functional consequences of such manipulation were observed by extracellular electrophysiology.

2광자 중합 마이크로 스케일 신경 세포 배양 장치의 3D 프린팅

Neuronal cultures have been a reference experimental model for several decades. However, 3D cell arrangement, spatial constraints on neurite outgrowth, ...

편광 신경 조직의 엔지니어링 3D 실크 콜라겐 기반 모델

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콜라겐 기반 스캐폴드를 사용한 신경모세포종의 3차원 체외 생체모방 모델

3 차원 조직 설계 정렬 사이토 네트워크 발달 메커니즘을 정리 하 고 신경 재생을 촉진 하

마이크로 전극 배열에 3D 엔지니어링의 연결을 문화의 인터페이스 : 혁신을

신경 시스템 재구성, 변조 및 모델링을 위해 해부학 적으로 영감을받은 3 차원 미세 조직 공학 신경 회로망

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