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Method Article
폴 리 (pentafluorophenyl 아크릴)의 준비에 대 한 프로토콜 (poly(PFPA)) 융합 실리 카 비즈 제공 됩니다. Poly(PFPA) 기능성된 표면 다음 항 체와 함께 움직일 하 고 immunoprecipitation 통해 단백질 분리에 대 한 성공적으로 사용.
폴 리 (pentafluorophenyl 아크릴)을 준비 하는 간단한 방법을 보여 줍니다 (poly(PFPA)) 융합 항 체 동원 정지 및 후속 immunoprecipitation (IP) 응용 프로그램에 대 한 실리 카 구슬. 간단한 2 단계 프로세스를 통해 poly(PFPA) 이식할된 표면 준비 된다. 첫 번째 단계에서 3-aminopropyltriethoxysilane (항)으로 링커 분자 실리 카 표면에 입금 됩니다. 두 번째 단계에서 poly(PFPA) 단일 중합체, 가역 추가 및 조각화 체인 전송 (뗏목) 중 합을 통해 합성에 pentafluorophenyl (PFP) 단위 사이 교환 반응을 통해 링커 분자에 투입 되는 폴리머와 항에 아민 그룹입니다. 항 및 실리 카 입자는 엑스레이 광전자 분광학 (XPS)에 의해 확인으로 입자 크기 변화에 의해 감시에 poly(PFPA)의 증 착 동적 산란 (DL)을 통해 측정. 구슬, 아민 기능성된 poly(ethylene glycol)와 poly(PFPA)의 부분 대체의 표면 화란 개선 (아미노 PEG)도 수행 됩니다. 못 대체 poly(PFPA) 실리 카 구슬 다음 IP 응용 프로그램에 대 한 항 체와 함께 움직일 수 투입. 데모, 단백질 키 니 아 제 RNA 활성화 (PKR)에 대 한 항 체, 고용 및 IP 효율 서쪽 blotting에 의해 결정 됩니다. 분석 결과 항 체 움직일 구슬 실제로 일반적인 단백질 상호 작용은 최소 PKR을 풍부 하 게 사용 될 수 있다는 것을 보여준다.
반응성 폴리머 브러쉬 최근 몇 년 동안에 많은 관심을 받았습니다. 활성화 된 표면 탐지 및 분리1,2,3,4,등의 분야에서 응용 프로그램과 함께 만드는 유기 또는 무기 재료에 기능성 분자를 고정을 사용할 수 있습니다. 5. 보고 반응 고분자 중 pentafluorophenyl 에스테 르 단위를 포함 하는 아민 및 가수분해6향해 저항 그들의 높은 반응성 때문에 특히 유용 합니다. 이러한 한 폴리머 poly(PFPA), 이며 1 차 또는 2 차 아민7,8,,910를 포함 하는 분자와 쉽게 기능성된 후 중 합 될 수 있습니다. 한 예로, poly(PFPA) 브러쉬 빛 반응 표면7만들려고 아미노 spiropyrans로 반응 했다.
Poly(PFPA)와 그 응용 프로그램의 준비 이전 간행물6,7,,89,10,11,12의 숫자에 설명 되었습니다. ,13,,1415,,1617. 특히, Theato와 동료 보고 "에 접목"와 "에서" 방법7,,810,,1112 접목을 통해 poly(PFPA) 브러쉬의 합성 . "접목 에" 접근 방식, 폴 리 (methylsilsesquioxane)에서-폴 리 (pentafluorophenyl 아크릴) (poly(MSSQ-PFPA)) 하이브리드 폴리머 합성된8,10,,1112했다. Poly(MSSQ) 구성 요소 형태로 강한 접착 코팅된 소재 표면에 브러시 레이어를 형성 하는 poly(PFPA) 구성 요소 되므로 다른 유기 및 무기 표면 수가 있었습니다. "접목 에서" 접근에서 표면 가역 추가 시작 하 고 조각화 체인 전송 (SI-뗏목) 중 합 poly(PFPA) 브러쉬7을 준비 하기 위해 고용 되었다. 이 경우에, 표면 고정된 체인 전송 에이전트 (SI-CTA) covalently silane 실리 카 반응을 통해 기판에 첨부를 먼저 되었다. 고정된 시 CTA 다음 기판에 안정적인 공유를 밀도가 포장된 poly(PFPA) 브러쉬 생성 PFPA 단위체의 뗏목 시 합에 참가 했다.
시-뗏목 중 합을 통해 합성 poly(PFPA) 브러쉬를 이용 하 여 우리는 최근 poly(PFPA) 융합 실리 카 입자와 단백질 정화18에서 그들의 후속 응용 프로그램에 항 체의 동원 정지를 시연. 항 체의 동원 정지에 대 한 poly(PFPA) 브러쉬를 사용 하 여 다양 한 IP 통해 현재 단백질 분리와 관련 된 문제를 해결 하기 위해 발견 되었다. 기존의 IP 항 체 immobilization19,,2021단백질 A/G는 링커로의 사용에 의존합니다. 이후 단백질 A/G를 사용 하 여 항 체를 특정 방향으로 장착할 수, 높은 대상 항 원 복구 효율성 달성 된다. 그러나, 단백질 A/G를 사용 하 여 단백질 복구, 둘 중 배경 잡음의 높은 수준에 기여 하는 동안 일반적인 단백질 상호 작용 뿐만 아니라 항 체의 손실에서 겪고 있다. 이러한 단점을 해결 하려면 고체 지원에 항 체의 직접 가교 탐험된22,,2324되었습니다. 이러한 기술의 효율은 일반적으로 낮은 가교 된 항 체의 임의의 방향으로. Poly(PFPA) 투입 기판에 대 한 항 체의 동원 정지는 영구적, PFP 단위 및 항 체에 아민 기능 사이 교환 반응을 통해 달성입니다. 비록 항 체 오리엔테이션은 여전히 무작위, 시스템 많은 반응 PFP 사이트, 중 합도 의해 제어 하는 데에서 혜택. 또한, 우리 아미노-말뚝와 PFP 단위의 부분 대체 하 여 보여주는 표면 화란 수 수 조정, 추가 시스템18의 단백질 복구 효율성을 향상. 전반적으로, poly(PFPA) 융합 실리 카 입자 합리적인 효율성 뿐만 아니라 많은 청소기 배경 전통적인 ip 효과적인 대안이 될를 표시 했다.
이 기여에 우리는 poly(PFPA) 이식할된 표면 항 체 동원 정지 및 IP 응용 프로그램에 대 한 준비 하는 다른 방법을 보고 합니다. 간단한 2 단계 프로세스에 그림 1에서 볼 수 있듯이 항 링커 분자는 먼저 입금 실리 카 표면에 그 후에 poly(PFPA) 폴리머 covalently에 PFP 단위 사이 반응을 통해 링커 분자에 연결 된 고분자 고 항에 아민 기능입니다. 이 준비 방법은 기판 표면에 poly(PFPA)의 영구 가교에 대 한 수 있지만 시 CTA 합성 및 poly(PFPA) 브러쉬의 중 합 시-뗏목과 관련 된 많은 합병증을 피 한다. 아미노 페그와 PFP 단위의 부분 대체 여전히 수행할 수 있습니다, 고분자 브러쉬 표면 특성의 미세 조정 허용. 우리는 따라서 준비 poly(PFPA) 융합 실리 카 구슬 항 체와 함께 움직일 수 및 IP 통해 단백질 농축 사용할 수 보여줍니다. 자세한 비드 준비 절차, 항 체 immobilization, 그리고 IP 테스트이 문서에 설명 되어 있습니다, 그리고 추구에 관심이 있는 독자에 대 한 기존의 단백질 A/G 대신 IP 기반.
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1입니다. Poly(PFPA) 단일 중합체의 준비
2. 준비 Poly(PFPA)의 공업화 SiO2 구슬
3. SiO2 의 준비 구슬 못 대체 Poly(PFPA)와 융합
4. 항 체 Immobilization Poly(PFPA)에 투입 SiO2 구슬
참고: 동일한 절차는 poly(PFPA)에 % 말뚝 대체에 사용 됩니다. TDW에서 PBS 태블릿을 용 해 하 여 버퍼링 하는 인산 염 (PBS)를 준비 합니다. PBS에 트윈-20의 1/1000을 추가 하 여 0.1% (v/v) 버퍼링 인산 염 분 트윈-20 (PBST)와 함께 준비 합니다.
5. 세포 세포의 용 해 및 Immunoprecipitation
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Poly(PFPA)의 준비에 대 한 회로도와 SiO2 구슬, 투입 하거나 못 없이 대체 그림 1에 표시 됩니다. 항와 접목 과정, 맨 손으로 SiO2 구슬, poly(PFPA) 항 기능성 SiO2 구슬, 그리고 poly(PFPA) 융합 SiO2 구슬 DL (그림 2)와 XPS (그림 3)에 의해 특징입니다. 구슬의 IP 효율성 서쪽 blotting에 의해 ?...
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Poly(PFPA)의 합성 SiO2 구슬은 그림 1에 나와 있는 투입. 채용 함으로써 항으로 링커 분자, poly(PFPA) 브러쉬 covalently SiO2 기판에 투입 간단한 2 단계 프로세스를 통해 준비 될 수 있습니다. PFP 단위 중 일부 항에 대 한 반응에 대 한 희생은, 비록 많은 PFP 단위 아미노 말뚝 또는 항 체 이상 반응에 대 한 사용할 수 있는 예상 된다. PFP 그룹 poly(PFPA) 브러쉬 할 물
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저자는 공개 없다.
이 작품 국방 개발 (부여 번호에 대 한 기관에 의해 지원 되었다 UD170039ID)입니다.
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Name | Company | Catalog Number | Comments |
2,2-Azobisisobutyronitrile, 99% | Daejung Chemicals | 1102-4405 | |
Methyl alcohol for HPLC, 99.9% | Duksan Pure Chemicals | d62 | |
Phenylmagnesium bromide solution 1.0 M in THF | Sigma-Aldrich | 331376 | |
Carbon disulfide anhydrous, ≥99% | Sigma-Aldrich | 335266 | |
Benzyl bromide, 98% | Sigma-Aldrich | B17905 | |
Petroleum ether, 90% | Samchun Chemicals | P0220 | |
Ethyl ether, 99% | Daejung Chemicals | 4025-4404 | |
Magnesium sulfate anhydrous, powder, 99% | Daejung Chemicals | 5514-4405 | |
Pentafluorophenyl acrylate | Santa Cruz Biotechnology | sc-264001 | contains inhibitor |
Aluminium oxide, activated, basic, Brockmann I | Sigma-Aldrich | 199443 | |
Sodium Chloride (NaCl) | Daejung Chemicals | 7548-4400 | |
Anisole anhydrous, 99.7% | Sigma-Aldrich | 296295 | |
Silica nanoparticle | Microparticles GmbH | SiO2-R-0.7 | 5% w/v aqueous suspension |
3-Aminopropyltrimethoxysilane, >96.0% | Tokyo Chemical Industry | T1255 | |
Dimethyl sulfoxide for HPLC, ≥99.7% | Sigma-Aldrich | 34869 | |
Amino-terminated poly(ethylene glycol) methyl ether | Polymer Source | P16082-EGOCH3NH2 | |
Phosphate buffered saline tablet | Takara | T9181 | |
Tween-20 | Calbiochem | 9480 | |
Tris-HCl (pH 8.0) | Invitrogen | AM9855G | |
KCl | Invitrogen | AM9640G | |
NP-40 | VWR | E109-50ML | |
Glycerol | Invitrogen | 15514-011 | |
Dithiothreitol | Biosesang | D1037 | |
Protease inhibitor | Merck | 535140-1MLCN | |
Bromo phenol blue | Sigma-Aldrich | B5525-5G | |
Tris-HCl (pH 6.8) | Biosolution | BT033 | |
Sodium dodecyl sulfate | Biosolution | BS003 | |
2-Mercaptoethanol | Gibco | 21985-023 | |
PKR Antibody | Cell Signaling Technology | 12297S | |
GAPDH Antibody | Santa Cruz Biotechnology | sc-32233 | |
Normal Rabbit IgG | Cell Signaling Technology | 2729S | |
HeLa | Korea Cell Line Bank | 10002 | |
Sonicator | DAIHAN Scientific | WUC-D10H | |
Ultrasonicator | BMBio | BR2006A | |
Centrifuge I | Eppendorf | 5424 R | |
Centrifuge II | LABOGENE | 1736R | |
Rotator | FINEPCR | ROTATOR/AG | |
Vacuum oven | DAIHAN Scientific | ThermoStable OV-30 | |
Gel permeation chromatography (THF) | Agilent Technologies | 1260 Infinity II | |
X-ray photoelectron spectrometer | Thermo VG Scientific | Sigma Probe | |
Dynamic light scattering | Malvern Instruments | ZEN 3690 |
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An erratum was issued for: Preparation of Poly(pentafluorophenyl acrylate) Functionalized SiO2 Beads for Protein Purification. Throughout the article, the term "3-aminopropyltriethoxysilane" has been replaced with "3-aminopropyltrimethoxysilane", and "APTES" with "APTMS".
The Keywords were updated from:
Poly(pentafluorophenyl acrylate), 3-aminopropyltriethoxysilane, reactive polymer brush, post-polymerization functionalization, antibody immobilization, immunoprecipitation
to:
Poly(pentafluorophenyl acrylate), 3-aminopropyltrimethoxysilane, reactive polymer brush, post-polymerization functionalization, antibody immobilization, immunoprecipitation
The Abstract was updated from:
We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent immunoprecipitation (IP) application. The poly(PFPA) grafted surface is prepared via a simple two-step process. In the first step, 3-aminopropyltriethoxysilane (APTES) is deposited as a linker molecule onto the silica surface. In the second step, poly(PFPA) homopolymer, synthesized via the reversible addition and fragmentation chain transfer (RAFT) polymerization, is grafted to the linker molecule through the exchange reaction between the pentafluorophenyl (PFP) units on the polymer and the amine groups on APTES. The deposition of APTES and poly(PFPA) on the silica particles are confirmed by X-ray photoelectron spectroscopy (XPS), as well as monitored by the particle size change measured via dynamic light scattering (DLS). To improve the surface hydrophilicity of the beads, partial substitution of poly(PFPA) with amine-functionalized poly(ethylene glycol) (amino-PEG) is also performed. The PEG-substituted poly(PFPA) grafted silica beads are then immobilized with antibodies for IP application. For demonstration, an antibody against protein kinase RNA-activated (PKR) is employed, and IP efficiency is determined by Western blotting. The analysis results show that the antibody immobilized beads can indeed be used to enrich PKR while non-specific protein interactions are minimal.
to:
We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent immunoprecipitation (IP) application. The poly(PFPA) grafted surface is prepared via a simple two-step process. In the first step, 3-aminopropyltrimethoxysilane (APTMS) is deposited as a linker molecule onto the silica surface. In the second step, poly(PFPA) homopolymer, synthesized via the reversible addition and fragmentation chain transfer (RAFT) polymerization, is grafted to the linker molecule through the exchange reaction between the pentafluorophenyl (PFP) units on the polymer and the amine groups on APTMS. The deposition of APTMS and poly(PFPA) on the silica particles are confirmed by X-ray photoelectron spectroscopy (XPS), as well as monitored by the particle size change measured via dynamic light scattering (DLS). To improve the surface hydrophilicity of the beads, partial substitution of poly(PFPA) with amine-functionalized poly(ethylene glycol) (amino-PEG) is also performed. The PEG-substituted poly(PFPA) grafted silica beads are then immobilized with antibodies for IP application. For demonstration, an antibody against protein kinase RNA-activated (PKR) is employed, and IP efficiency is determined by Western blotting. The analysis results show that the antibody immobilized beads can indeed be used to enrich PKR while non-specific protein interactions are minimal.
The fourth paragraph of the Introduction was updated from:
In this contribution, we report an alternative method to prepare poly(PFPA) grafted surface for antibody immobilization and IP application. In a simple two-step process, as illustrated in Figure 1, an APTES linker molecule is first deposited onto the silica surface, then the poly(PFPA) polymer is covalently attached to the linker molecule through the reaction between the PFP units on the polymer and the amine functions on APTES. This preparation method allows for the permanent crosslinking of poly(PFPA) to a substrate surface, but avoids the many complications associated with SI-CTA synthesis and SI-RAFT polymerization of poly(PFPA) brushes. Partial substitution of the PFP units with amino-PEG can still be performed, allowing fine-tuning of the polymer brush surface properties. We show the poly(PFPA) grafted silica beads thus prepared can be immobilized with antibodies and used for protein enrichment via IP. The detailed bead preparation procedure, antibody immobilization, and IP testing are documented in this article, for readers interested in seeking an alternative to conventional Protein A/G based IP.
to:
In this contribution, we report an alternative method to prepare poly(PFPA) grafted surface for antibody immobilization and IP application. In a simple two-step process, as illustrated in Figure 1, an APTMS linker molecule is first deposited onto the silica surface, then the poly(PFPA) polymer is covalently attached to the linker molecule through the reaction between the PFP units on the polymer and the amine functions on APTMS. This preparation method allows for the permanent crosslinking of poly(PFPA) to a substrate surface, but avoids the many complications associated with SI-CTA synthesis and SI-RAFT polymerization of poly(PFPA) brushes. Partial substitution of the PFP units with amino-PEG can still be performed, allowing fine-tuning of the polymer brush surface properties. We show the poly(PFPA) grafted silica beads thus prepared can be immobilized with antibodies and used for protein enrichment via IP. The detailed bead preparation procedure, antibody immobilization, and IP testing are documented in this article, for readers interested in seeking an alternative to conventional Protein A/G based IP.
Step 2.1 of the Protocol was updated from:
Treatment of SiO2 beads with APTES
to:
Treatment of SiO2 beads with APTMS
Step 2.1.1 of the Protocol was updated from:
SiO2 particles are available in the form of a 5% (w/v) aqueous suspension. Combine 0.8 mL of SiO2 suspension with 40 mg of APTES and 8 mL of methanol in a 20 mL scintillation vial equipped with a stir bar.
to:
SiO2 particles are available in the form of a 5% (w/v) aqueous suspension. Combine 0.8 mL of SiO2 suspension with 40 mg of APTMS and 8 mL of methanol in a 20 mL scintillation vial equipped with a stir bar.
Step 2.1.3 of the Protocol was updated from:
Transfer the solution to a conical tube. To isolate the APTES functionalized SiO2 beads, centrifuge the solution at 10,000 x g for 5 min, then remove the supernatant. Wash the beads by re-dispersing them in 3 mL of fresh methanol. Shake the tube by hand for mixing, but if necessary, improve the dispersion by sonication in a water bath for a few seconds. Centrifuge the beads at 10,000 x g for 5 min. Remove the supernatant and repeat the wash step one more time.
to:
Transfer the solution to a conical tube. To isolate the APTMS functionalized SiO2 beads, centrifuge the solution at 10,000 x g for 5 min, then remove the supernatant. Wash the beads by re-dispersing them in 3 mL of fresh methanol. Shake the tube by hand for mixing, but if necessary, improve the dispersion by sonication in a water bath for a few seconds. Centrifuge the beads at 10,000 x g for 5 min. Remove the supernatant and repeat the wash step one more time.
Step 2.1.4 of the Protocol was updated from:
Combine the methanol washed SiO2 beads with 3 mL of dimethyl sulfoxide (DMSO). Shake the mixture by hand, or if necessary sonicate for a few seconds, until the beads are fully dispersed in DMSO. Centrifuge the beads at 10,000 x g for 5 min, then remove the supernatant. Repeat the step to ensure complete solvent exchange from methanol to DMSO.to:
Combine the methanol washed SiO2 beads with 3 mL of dimethyl sulfoxide (DMSO). Shake the mixture by hand, or if necessary sonicate for a few seconds, until the beads are fully dispersed in DMSO. Centrifuge the beads at 10,000 x g for 5 min, then remove the supernatant. Repeat the step to ensure complete solvent exchange from methanol to DMSO.
NOTE: The final suspension contains the APTMS functionalized SiO2 beads dispersed in 4 mL of DMSO.
Step 2.2 of the Protocol was updated from:
Grafting poly(PFPA) to APTES functionalized SiO2 beads
to:
Grafting poly(PFPA) to APTMS functionalized SiO2 beads
Step 2.2.2 of the Protocol was updated from:
Add 1 mL of APTES functionalized SiO2 beads suspended in DMSO (from Step 2.1.4) to the poly(PFPA) solution. React at RT for 1 h with vigorous stirring.
to:
Add 1 mL of APTMS functionalized SiO2 beads suspended in DMSO (from Step 2.1.4) to the poly(PFPA) solution. React at RT for 1 h with vigorous stirring.
Step 3.4 of the Protocol was updated from:
To prepare APTES functionalized SiO2 beads suspended in DMSO, follow the same steps shown in Step 2.1. Transfer 1 mL of the bead suspension into the PEG-substituted poly(PFPA) solution prepared in Step 3.3. Allow the grafting between poly(PFPA) and APTES functionalized SiO2 beads to proceed at RT for 1 h with vigorous stirring.
to:
To prepare APTMS functionalized SiO2 beads suspended in DMSO, follow the same steps shown in Step 2.1. Transfer 1 mL of the bead suspension into the PEG-substituted poly(PFPA) solution prepared in Step 3.3. Allow the grafting between poly(PFPA) and APTMS functionalized SiO2 beads to proceed at RT for 1 h with vigorous stirring.
The first paragraph of the Representative Results was updated from:
A schematic for the preparation of poly(PFPA) grafted SiO2 beads, with or without PEG substitution is shown in Figure 1. To monitor the APTES and poly(PFPA) grafting process, bare SiO2 beads, APTES functionalized SiO2 beads, and poly(PFPA) grafted SiO2 beads are characterized by both DLS (Figure 2) and XPS (Figure 3). IP efficiencies of the beads are determined by Western blotting. Figure 4 shows the Western blotting results for IP using 1% PEG-substituted poly(PFPA) grafted beads, where the beads are incubated with no antibody, a non-specific antibody, or anti-PKR antibody. Figure 5 shows the Western blotting results for IP using 0% PEG-substituted poly(PFPA) grafted beads and 1% PEG-substituted poly(PFPA) grafted beads, both incubated with anti-PKR antibodies.
to:
A schematic for the preparation of poly(PFPA) grafted SiO2 beads, with or without PEG substitution is shown in Figure 1. To monitor the APTMS and poly(PFPA) grafting process, bare SiO2 beads, APTMS functionalized SiO2 beads, and poly(PFPA) grafted SiO2 beads are characterized by both DLS (Figure 2) and XPS (Figure 3). IP efficiencies of the beads are determined by Western blotting. Figure 4 shows the Western blotting results for IP using 1% PEG-substituted poly(PFPA) grafted beads, where the beads are incubated with no antibody, a non-specific antibody, or anti-PKR antibody. Figure 5 shows the Western blotting results for IP using 0% PEG-substituted poly(PFPA) grafted beads and 1% PEG-substituted poly(PFPA) grafted beads, both incubated with anti-PKR antibodies.
Figure 1 was updated from:
Figure 1: Schematic for the preparation of poly(PFPA) grafted SiO2 beads using APTES as a linker molecule. (a) Poly(PFPA) grafted beads. (b) Partially PEG-substituted poly(PFPA) grafted beads.
to:
Figure 1: Schematic for the preparation of poly(PFPA) grafted SiO2 beads using APTMS as a linker molecule. (a) Poly(PFPA) grafted beads. (b) Partially PEG-substituted poly(PFPA) grafted beads.
Figure 2 was updated from:
Figure 2: DLS measurements for (a) bare SiO2 beads (SiO2), (b) APTES functionalized SiO2 beads (APTES-SiO2), and (c) poly(PFPA) grafted SiO2 beads (poly(PFPA)-SiO2), dispersed in DMSO. The Z-average diameter (d) and polydispersity index (PDI) of each sample are reported.
to:
Figure 2: DLS measurements for (a) bare SiO2 beads (SiO2), (b) APTMS functionalized SiO2 beads (APTMS-SiO2), and (c) poly(PFPA) grafted SiO2 beads (poly(PFPA)-SiO2), dispersed in DMSO. The Z-average diameter (d) and polydispersity index (PDI) of each sample are reported.
Figure 3 was updated from:
Figure 3: XPS spectra for bare SiO2 beads (SiO2), APTES functionalized SiO2 beads (APTES-SiO2), and poly(PFPA) grafted SiO2 beads (poly(PFPA)-SiO2). The peaks examined correspond to (a) Si 2p, (b) O 1s, (c) N 1s, and (d) F 1s.
to:
Figure 3: XPS spectra for bare SiO2 beads (SiO2), APTMS functionalized SiO2 beads (APTMS-SiO2), and poly(PFPA) grafted SiO2 beads (poly(PFPA)-SiO2). The peaks examined correspond to (a) Si 2p, (b) O 1s, (c) N 1s, and (d) F 1s.
The first and second paragraphs of the Discussion were updated from:
The synthesis of poly(PFPA) grafted SiO2 beads is illustrated in Figure 1. By employing APTES as a linker molecule, poly(PFPA) brushes covalently grafted to SiO2 substrate can be prepared via a simple two-step process. Although some of the PFP units are sacrificed for the reaction with APTES, a large number of the PFP units are expected to remain available for later reaction with either amino-PEG or antibodies. The PFP groups are known to form low energy surfaces so poly(PFPA) brushes do not solvate well in water28. For IP application, the antibodies need to be immobilized on the poly(PFPA) brushes, and this exchange reaction is done in aqueous buffer solution in order to preserve the activity of the antibodies. As reported in our previous publication, partial substitution of the PFP units with hydrophilic molecules such as amine-functionalized PEG can improve surface hydrophilicity, leading to increased antibody immobilization efficiency18. In this study, partially PEG substituted poly(PFPA) is also prepared, then grafted to the SiO2 surface using the same APTES linker molecule. Overall, the methods illustrated in Figure 1 allow the preparation of poly(PFPA) grafted surfaces with different degrees of PEG substitution. These polymer brushes with tunable surface properties provide an ideal platform for antibody immobilization and subsequent IP application.
The bead preparation process is monitored by both DLS and XPS. The DLS results for various functionalized SiO2 beads in DMSO are summarized in Figure 2. The bare SiO2 beads exhibit hydrodynamic diameter of 666 nm, in agreement with the manufacturer reported bead size (0.676 μm; SD = 0.03 μm). After APTES treatment, the bead diameter increases to 740 nm; and with poly(PFPA) treatment, the bead diameter further increases to 1889 nm. It is important to point out that the polydispersity index (PDI) for the poly(PFPA) grafted beads is rather large (PDI = 0.76), which is indicative of poor quality sample containing large aggregates. Although the DLS curve only shows one nano-sized peak, small amount of aggregates may be present in the suspension. The functionalized SiO2 beads are also examined by XPS to determine surface composition (Figure 3). Following APTES treatment, N 1s peak associated with the amine groups on APTES is detected. And, following poly(PFPA) treatment, F 1s peak associated with the PFP units on the polymer is detected. Together these data show the successful functionalization of the SiO2 surface, first with APTES, then with poly(PFPA).
to:
The synthesis of poly(PFPA) grafted SiO2 beads is illustrated in Figure 1. By employing APTMS as a linker molecule, poly(PFPA) brushes covalently grafted to SiO2 substrate can be prepared via a simple two-step process. Although some of the PFP units are sacrificed for the reaction with APTMS, a large number of the PFP units are expected to remain available for later reaction with either amino-PEG or antibodies. The PFP groups are known to form low energy surfaces so poly(PFPA) brushes do not solvate well in water28. For IP application, the antibodies need to be immobilized on the poly(PFPA) brushes, and this exchange reaction is done in aqueous buffer solution in order to preserve the activity of the antibodies. As reported in our previous publication, partial substitution of the PFP units with hydrophilic molecules such as amine-functionalized PEG can improve surface hydrophilicity, leading to increased antibody immobilization efficiency18. In this study, partially PEG substituted poly(PFPA) is also prepared, then grafted to the SiO2 surface using the same APTMS linker molecule. Overall, the methods illustrated in Figure 1 allow the preparation of poly(PFPA) grafted surfaces with different degrees of PEG substitution. These polymer brushes with tunable surface properties provide an ideal platform for antibody immobilization and subsequent IP application.
The bead preparation process is monitored by both DLS and XPS. The DLS results for various functionalized SiO2 beads in DMSO are summarized in Figure 2. The bare SiO2 beads exhibit hydrodynamic diameter of 666 nm, in agreement with the manufacturer reported bead size (0.676 μm; SD = 0.03 μm). After APTMS treatment, the bead diameter increases to 740 nm; and with poly(PFPA) treatment, the bead diameter further increases to 1889 nm. It is important to point out that the polydispersity index (PDI) for the poly(PFPA) grafted beads is rather large (PDI = 0.76), which is indicative of poor quality sample containing large aggregates. Although the DLS curve only shows one nano-sized peak, small amount of aggregates may be present in the suspension. The functionalized SiO2 beads are also examined by XPS to determine surface composition (Figure 3). Following APTMS treatment, N 1s peak associated with the amine groups on APTMS is detected. And, following poly(PFPA) treatment, F 1s peak associated with the PFP units on the polymer is detected. Together these data show the successful functionalization of the SiO2 surface, first with APTMS, then with poly(PFPA).
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