ここに報告された作品は、オーバーン大学AUDFSとUSAF CRADA 07から277-60MDG-01からの補助金によって支えられて。この記事の見解は著者のものであり、アメリカ空軍、国防総省、または米国政府の公式政策や立場を反映するものではありません。

1。ステージの設定<ol><li>型株S.を得る球菌 ATCC 12600、S.球菌 ATCC 27690及び枯草菌 ATCC 6051。 S.のメチシリン耐性株黄色ブドウ球菌 - MRSA1、MRSA 2、MRSA 5、MRSA 13、MRSA 26、MRSA 34、MRSA 45、B.炭疽スターン、 ネズミチフス菌 LT2、 赤痢菌、エルシニアenterocolotica、プロテウス·ミラビリス、肺炎桿菌 13882;溶菌ファージ12600。 </li><li> PBP 2aは抗体共役ラテックスビーズを入手します。 </li><li> 21に記載されているようNZY培地を準備します。 </li><li>食塩水（PBS）をリン酸緩衝を得る。 </li><li>ラングミュア·ブロジェット（LB）単分子層堆積のためのサブフェーズとして脱イオン水を準備します。 </li></ol> 2。バクテリオファージの伝播と滴定<ol><li> Sの一晩培養を5mlをインキュベート球菌 ATCC 12600ファージを500μl（3×10 9 &lt;と（3.6×10 8コロニー形成単位（CFU）/ ml）を/ 37℃で一晩振盪インキュベーターで2 Lフラック500ミリリットルNZY培地で）&gt; PFU / mlの（商標）。 </li><li> 4℃で10分のために4,424 xgで文化を遠心</li><li> 4℃で10分間、11,325×gで再遠心上清℃で</li><li> 0.22μmのミリポアフィルターを通してフィルター上澄み。 </li><li> 1.5時間75395 xgでろ液を遠心分離します。 </li><li>蒸留水100μlのペレットを溶解する。 </li><li> NZY培地でファージ懸濁液の10倍希釈液を調製する。 </li><li> Sの（ON）一晩培養のプレート1ミリリットルすべての表面が覆われていることを確認するためNZY寒天と2プレートの各々の上に黄色ブドウ球菌 ATCC 12600を。文化の過剰を削除し、30分間、表面が乾燥してみましょう。 </li><li>プレートの表面に適当なファージ希釈のサンプル（10μL）を発見し、18から24時間、37°C ​​のでインキュベート。 </li><li>プラークの形成を調べ、ファージ力価を計算します。バクテリオファージ力価（T）は、ウェブ数に基づいて推定されるファージサスペンションと希釈係数（F）10μlの体積（V）ごとに形成laques（N）。 。Tは= N /（VXF）たとえば、希釈10 -7でのプラーク数75と体積10μlの（10×10 -3 ml）のために、力価が75 /等しいです：力価は、次の式により算出した（10×10 -3×10 -7）= 7.5×10 10プラーク形成単位（PFU）あたりのmlの懸濁液。 </li></ol> 3。ゴールド固定化ファージ<ol><li> 10分間アルゴンのプラズマエッチングによってクリーンゴールドコーティングされた水晶片（60ミリメートル2）した後、滅菌キャビネットにUV光の下で6時間殺菌する。 </li><li>滅菌シャーレ内の各部分の金表面に1×10 9 PFU / mlのファージ懸濁液の50マイクロリットルを追加し、室温で湿潤チャンバー内で一晩インキュベートする。 </li><li>残りファージ懸濁液を取り出して、滴定。 </li><li>アンバウンドを除去するためにPBSで結合したファージと片5回洗浄ファージ。 </li></ol> 4。乾燥した表面上に固定化されたファージ感染のテスト<ol><li> NZY寒天プレート上にS。球菌 ATCC 12600のO / N文化を広げ、乾燥させることができます。 </li><li>板面上に固定化したファージとゴールドピースを下に置きます。 </li><li>感染性を示している℃で37℃で12時間インキュベートした後溶解のゾーンを守ってください。 </li><li>対照実験のないファージを金覆わ片を使用してください。 </li></ol> 5。液体中の遊離と結合したファージの溶解活性のテスト<ol><li> S.のON文化を追加4 300ミリリットルサイドアームフラスコ（各フラスコに6×10 6 CFU / ml）を毎におけるNZYのブドウ球菌 ATCC 12600〜10ミリリットル。 </li><li> 2フラスコ2×10 6 PFU /遊離ファージmlのアドイン。 </li><li>コントロールとして他の二つのフラスコを使用してください。 </li><li> S.の経時変化を監視するすべてのフラスコを30分間隔で光学密度測定（OD 600）により、570分間球菌細胞溶解。</li><li> 24時間での最終的な測定を行います。 </li><li>手順5.1から5.5を繰り返しますが、コントロールフラスコのないファージを金結合したファージの代わりに自由にファージと片、金の部分を使用しています。 </li></ol> 6。インキュベーション中に結合したファージの損失<ol><li>室温で一晩湿気のチャンバー内に配置されたペトリ皿中の滅菌金片の表面に1×10 9 PFU / mlのファージ50μlのを追加します。 </li><li>金表面と力価から非結合ファージとサスペンションを取り外します。 </li><li> 8時間37℃で5 PBSで倍と場所シェーカー·インキュベーター、15 mlチューブに、1mlのNZY溶液中の結合したファージとの金の部分を洗う。 </li><li> 2で説明したように切 ​​り離されたファージの力価を決定します。 </li></ol> 7。ファージスフェロイドの準備<ol><li> 1ミリリットルバイアルで分光等級のクロロホルム等量と在庫ファージ12600懸濁液400μlの（10 11 PFU / ml）を組み合わせる室温で加えた。 </li><li>優しくボルテックス1分持続オーバーファージ - クロロホルムサスペンション5-6回（5秒間隔）。 </li><li>懸濁液を30秒間安定化させ、次いでスフェロイドを含む上相をピペットで単層の準備のためにオフにピペッティングした。 </li><li>伝送および走査型電子顕微鏡用スフェロイドサスペンション数マイクロリットルを取る。 </li><li>バイオセンサー製造の残りの回転楕円体サスペンションを使用してください。 </li></ol> 8。バイオセンサーの準備<ol><li> 10分PDC-32G Harrickプラズマクリーナー、アルゴンのプラズマエッチングによってクリーンQCM-Dセンサー。 </li><li>任意の有機不純物を除去するためにヘキサンでセンサーを洗浄します。 </li><li> 22で説明したように、フィルムバランスのトラフを準備し、清掃してください。 </li><li>副相溶液とLBトラフを記入し、20℃±0.1℃をトラフ障壁とそれをきれいにし、トラフを安定</li><li>水性suspensiにおけるファージ12600300μlのアリコートを広げLBサブフェーズへ（10 11 PFU / ml）を上に。 </li><li>部分的に副相22,23に浸漬する傾斜水和ガラス棒を下に実行するためにファージ12600水性懸濁液（10 11 PFU / ml）を300μlのアリコートを可能にすることにより、LBサブフェーズ·ソリューションにファージ単層を準備します。 </li><li> 10分間準備された単層を安定化した後、定圧19 N / mのが達成されるまで30 50mm /分（44 cm 2で/分）の速度でそれを圧縮する。 </li><li>連続して単層のうちに7回センサーを浸漬することにより4.5ミリメートル/分の速度で垂直に配置QCM-Dセンサに垂直成膜を実行します。細菌試料への曝露の前に堆積ファージ単層の電子顕微鏡は、層が均質で連続であることを示し、均一（データは示さず）。 </li><li>繰り返し3で調製されたファージ回転楕円体懸濁液を用いて4.5から4.8を繰り返します。 </li><li> MRSA検出、電子のために製造されたファージのバイオセンサーを使用して、顕微鏡、およびエリプソメトリ。 </li></ol> 9。バイオセンサーテスト、メチシリン耐性および感受性黄色細菌の識別<ol><li>このプロトコルでは、未変性および変性ファージとファージスフェロイドを有するバイオセンサが用意されている。 4つのセンサ流室を有する水晶振動子マイクロバランスがQCMセンサー表面に固定化ファージを細菌の結合を監視するために使用される。 PBP 2aは抗体共役ラテックスビーズは、メチシリン耐性（MRSA）および感受性黄色ブドウ菌を区別するために利用される。すべての測定は5 MHzでフローモード（50μL/分）で行われる。 </li><li>水中でQCMセンサ（〜30分）のベースラインの共振周波数を確立する。 </li><li>テストセルを通る水でのライブメチシリン感受性黄色細菌細胞（10 9 CFU / ml）の懸濁液を描画します。 </li><li>連続的に第一の倍音、USIのためのセンサの共振周波数とエネルギー散逸の変化を監視ngのQ-ソフトソフトウェア。 </li><li>センサの共振周波数及び損失の変化が飽和レベルに達したときに、周波数及び損失の連続監視中に流れるようにPBP抗体共役ラテックスビーズの懸濁液（6.77×10 10粒子/ ml）を加える。 </li><li>繰り返しメチシリン耐性黄色ブドウ球菌の細菌細胞（MRSA）が9.2から9.5を繰り返します。 </li><li> Cは質量感度が一定である（5 MHzでC = 17.7 ngのX cm -2のX Hzで-1 Sauerbrey方程式24,25 量Δf=-ΔmをXN / C、による結合細菌に起因する質量変化を通じて、周波数変化を定義）、mは質量であり、nは倍音の数（n = 1）である。 </li><li>記録からのエネルギー散逸変化（ΔD）を定義する振動の指数関数的減衰（周波数および振幅は振動の一周期の間に消費されると、蓄積されたエネルギーの定量化を可能にする、減衰、それぞれ、Eは 散逸し、Eが 格納されている ：ΔD = E 消散 / 2πEを 格納 。 ΔDは放熱ユニット（DU）は1 DU = 10 -6相対単位）で測定される。 </li></ol>

<ol>
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G. M., Tufenkji, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+Capture+Efficiency+and+Antimicrobial+Activity+of+Phage-Functionalized+Model+Surfaces.">Bacterial Capture Efficiency and Antimicrobial Activity of Phage-Functionalized Model Surfaces.</a> Langmuir. 27, 5472-5480 (2011).</li><li>Schofield, D. A., Molineux, I. J., Westwater, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioluminescent'+Reporter+Phage+for+the+Detection+of+Category+A+Bacterial+Pathogens.">Bioluminescent' Reporter Phage for the Detection of Category A Bacterial Pathogens.</a> J. Vis. Exp. (53), e2740 (2011).</li><li>Voinova, M. V., Jonson, M., Kasemo, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Missing+mass"+effect+in+biosensor's+QCM+applications.">Missing mass" effect in biosensor's QCM applications.</a> Biosens. Bioelectron. 17, 835-841 (2002).</li><li>Gervals, L., Gel, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immobilization+of+biotinylated+bacteriophages+on+biosensor+surfaces.">Immobilization of biotinylated bacteriophages on biosensor surfaces.</a> Sensors and Actuators. 125, 615-621 (2007).</li><li>Nanduri, V., Sorokulova, I. B., Samoylov, A. M., Simonian, A. L., Petrenko, V. A., Vodyanoy, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phage+as+a+molecular+recognition+element+in+biosensors+immobilized+by+physical+adsorption.">Phage as a molecular recognition element in biosensors immobilized by physical adsorption.</a> Biosens. Bioelectron. 22, 986-992 (2007).</li><li>Sorokulova, I., Watt, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+biopolymer+for+preservation+of+microorganisms+during+sampling+and+storage.">Natural biopolymer for preservation of microorganisms during sampling and storage.</a> J. Microbiol. Methods. 88, 140-146 (2012).</li><li>Sanders, E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aseptic+Laboratory+Techniques:+Plating+Methods.">Aseptic Laboratory Techniques: Plating Methods.</a> J. Vis. Exp. (63), e3064 (2012).</li></ol>

著者は、彼らが競合する経済的利益を持っていないことを宣言します。

それはよくファージを細菌性病原体28バイオセンサープローブとして使用できることが知られている。急速な差別抗生物質耐性および感受性株：これは、PBP 2aの抗体と一緒にファージは、古い問題を解決するために利用できることは、この研究で実証されている。 しかしながら、それらの正常な未変性ブドウ球菌ファージは、彼らが細菌に結合するにもかかわら?...

黄色ブドウ球菌のメチシリン耐性株は、本質的な感染症や院内アウトブレイク4-8の要因として示唆されている。このようなディスク拡散オキサシリン寒天スクリーンテスト、または微量液体希釈としてメチシリン耐性の認識の一般的な方法は、耐性の発現量を高めるために合わせた培養条件に依存している。変化は、成長培地に30または35でオキサシリン、インキュベーションの活用°Cではなく37℃以上、およびNaClのインクルージョンが含まれています。さらに、これらの種類の技法が正しい検出のため、24時間の代わりに16〜18時間の長い潜伏期間が必要である。メチシリン耐性を同定するための感度の適切な（&gt; 96％）レベルの急速な技術は、バイテックGPS-SAカード、ラピッドATB黄色ブドウ球菌システム、及び3-11時間後に結果を生成する高速マイクロスキャンパネルシステムのような自動化された微量希釈法を含む9-11。クリスタルMRSA IDシステムは、Sの成長の認識に基づいて迅速な方法である2％NaClおよび酸素感受性蛍光センサー付リットルあたりオキサシリン4mgの存在下での黄色ブドウ球菌 。 91から100パーセントの間で感度の範囲は、インキュベーション12-14の4時間後に主張した。これらの表現型の方法は、異種の抵抗を発現普及している菌株の影響によりその精度が制限されている。したがって、メチシリン耐性の認識のための最高の広く受け入れられている方法はmecAの遺伝子15のPCRまたはDNAハイブリダイゼーションである。しかしこの手法は、精製されたDNAを必要とし、細胞の破片16を含む様々な混和剤（不純物）に非常に敏感です。 さらに、これらの技術は実行するのに長い時間を必要とする。 mecAの遺伝子産物、蛋白質PBP 2aとの認識戦略は抵抗を決定するために利用することができ、標準試験法17に比べて信頼性があってもよい。 1,2,18を有するものを含む黄色ブドウ球菌株の認識プローブとして利用することができることが示された。本研究ではこのようなリアルタイムでMRSAのコンフォメーションと一緒に細菌の認識などのMRSAの特異的認識と検出における新規手法を提案した。この特定の目的のためのS.タンパク質に対するモノクローナル抗体と組み合わせたホストの広いスペクトル（MRSA株を含む）と黄色ブドウ球菌バクテリオファージは、（PBP 2a）が使用されている。 PBP 2aは、細胞壁タンパク質であり、それはMRSAの抗生物質抵抗性の原因である。しかしPBP 2aの抗体は、S.のために固有のものではありませんいくつかの他の細菌から黄色ブドウ球菌は、PBP 2A 19,20に配列類似性と抗生物質結合タンパク質を持っている。そこで本研究では、S. PBP 2aの蛋白質に対する黄色ブドウ球菌バクテリオファージおよび抗体が使用されている。納入仕様にバイオセンサーを開発することができるようにする的に二段階のアクションが利用されていると、デバイスを検出し、MRSAを識別します。最初のステップは、Sを使用センサプローブとして球菌バクテリオファージ単層、2番目のステップはPBP 2A特異的な抗体を用いている。したがって、人はS.を認識し、手順黄色ブドウ球菌の細菌は、他の一人としての抗生物質結合タンパク質に敏感になります。二つのステップから受信された信号が正である場合には、MRSAの特異的検出を示す。

<table border="1">
		<tbody>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Reagents</td>
		 </tr>
		 <tr>
			<td>Phosphate buffered saline (PBS) </td>
			<td>Sigma-Aldrich, St. Louis, MO</td>
			<td>P4417 </td>
			<td></td>
		 </tr>
		 <tr>
			<td>spectrophotometric-grade chloroform </td>
			<td>Sigma-Aldrich, 
				St. Louis, MO </td>
			<td>154733 </td>
			<td>(99.8% A.C.S.) </td>
		 </tr>
		 <tr>
			<td>Hexane-Anhydrous </td>
			<td>Sigma-Aldrich, 
				St. Louis, MO</td>
			<td>29609-0</td>
			<td>(95%)</td>
		 </tr>
		 <tr>
			<td>Ethyl Alcohol </td>
			<td>Pharmco products Inc. Brookfield, CT </td>
			<td>64-17-5</td>
			<td>190 Proof</td>
		 </tr>	
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Equipment</td>
		 </tr>
		 <tr>
			<td>PBP 2a antibody conjugated latex beads</td>
			<td>Denka Seiken Co., Ltd, Tokyo, Japan</td>
			<td>The MRSA-Screen test</td>
			<td></td>
		 </tr>
		 <tr>
			<td>S. aureus ATCC 12600, S. aureus ATCC 27690 and Bacillus subtilis ATCC 6051 from </td>
			<td>American Type Culture Collection (Manassas, VA);</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>MRSA1, MRSA 2, MRSA 5, MRSA 13, MRSA 26, MRSA 34, MRSA 45, B. anthracis Sterne, Salmonella typhimurium LT2, Shigella flexneri, Yersinia enterocolotica, Proteus mirabilis, Klebsiella pneumoniae 13882; The lytic phage 12600 </td>
			<td>The culture collection of Auburn University, Auburn, AL</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>Centrifuge </td>
			<td>Beckman Coulter</td>
			<td>Optima L-90K
				Ultra Centrifuge</td>
			<td></td>
		 </tr>
		 <tr>
			<td>KSV 2200 LB film balance</td>
			<td>KSV Chemicals, Finland</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>Light microscope optical system </td>
			<td>CitoViva Technology Inc., Auburn, AL </td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>QCM-D</td>
			<td>Q-Sense AB, V&auml;stra Fr&ouml;lunda, Sweden </td>
			<td>E4</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Scanning electron microscope (SEM)</td>
			<td>JEOL USA Inc., Peabody, MA</td>
			<td>JEOL-7000F SEM </td>
			<td></td>
		 </tr>
		 <tr>
			<td>Transmitting electron microscopy (TEM)</td>
			<td>JEOL USA Inc., Peabody, MA</td>
			<td>JEOL, JEM 2010 </td>
			<td></td>
		 </tr>
		 <tr>
			<td>Stericup, Presterilized</td>
			<td>Millipore Corporation, Billerica, MA</td>
			<td>SCGPU05RE</td>
			<td>0.22 &mu;m, GP Express PLUS membrane</td>
		 </tr>
		 <tr>
			<td>Bio-Assay dish</td>
			<td>NUNC A/S, Denmark</td>
			<td>240835</td>
			<td>Dimensions(mm), 245 x 245 x 25</td>
		 </tr>
		 <tr>
			<td>Pipettes</td>
			<td>Gilson, Pipetman, France</td>
			<td>P100, P200, P1000</td>
			<td></td>
		 </tr>
		 <tr>
			<td>C24 Incubator Shaker</td>
			<td>New Brunswick Scientific, CT</td>
			<td>Classic C24</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Gold-coated quartz pieces</td>
			<td>Auburn University, AL</td>
			<td></td>
			<td>Homemade</td>
		 </tr>
		 <tr>
			<td>Petri dishes</td>
			<td>Fisher Brand, USA</td>
			<td>0875713</td>
			<td>100 mmX15 mm </td>
		 </tr>
		 <tr>
			<td>SterilGard III Advance</td>
			<td>The Baker Company, ME</td>
			<td>SG403</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Culture Growing Flasks</td>
			<td>Corning Incorporated, NY</td>
			<td>4995</td>
			<td>PYREX 250 ml Erlenmeyer flasks </td>
		 </tr>
		 <tr>
			<td>Optical Spectrometer</td>
			<td>Genesys 20. Thermo Spectronic, USA.</td>
			<td>4001</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Plasma Cleaner</td>
			<td>Harrick Plasma, USA</td>
			<td>PDC-32G</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Millipore water purification system</td>
			<td>Millipore</td>
			<td>Direct-Q</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Imaging Ellipsometer</td>
			<td>Accurion, USA</td>
			<td>nanofilm_ep3se
			</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Software </td>
			<td>Q-Sense AB, Sweden</td>
			<td>QSoft, QTools</td>
			<td></td>
		 </tr>
		</tbody>
 </table>

biosensor for detection of antibiotic resistant staphylococcus bacteria

黄色ブドウ球菌株の広い宿主範囲およびペニシリン結合タンパク質（PBP 2a）の抗体共役ラテックスビーズは、メチシリン耐性（MRSA）および感受性（MSSA）Sの識別用に設計されたバイオセンサーを作成するために利用されているを有する構造的に形質転換された溶菌バクテリオファージ。ブドウ種 1,2。溶菌ファージは、水 - クロロホルムインタフェースとの接触によりファージスフェロイドに変換されている。ファージスフェロイド単層をラングミュア·ブロジェット（LB）法3でバイオセンサー表面上に移動されました。作成されたバイオセンサーは、細菌ファージの相互作用を評価するための放熱追跡と水晶振動子マイクロバランス（QCM-D）によって検討されている。細菌スフェロイド相互作用が減少し、共振周波数とMRSAとMSSA株の両方の消費エネルギーの上昇につながった。細菌結合した後、これらのセンサは、さらにペニシリン結合タンパク質抗体ラテックスビーズにさらされているS。 MRSAで分析センサーは2A抗体ビーズをPBPに応え、MSSAで検査センサーが応答を与えませんが。この実験的な区別は、メチシリン耐性と敏感S.間に明確な区別を決定黄色ブドウ球菌株 。同じようにバインドされ、バインドされていないバクテリオファージは、表面上、水懸濁液中の細菌の増殖を抑制する。溶菌ファージをスフェロイドに変更されると、彼らは強力な溶解活性を保持し、高い細菌の捕獲能力を示しています。ファージとファージスフェロイドは、抗生物質耐性微生物のテストおよび滅菌のために利用することができる。他のアプリケーションは、バクテリオファージ療法および抗菌面での使用を含むことができる。

ファージは、Sのすべてのテストされた株に対して溶菌活性を示しとしてファージスポット試験によって示さMRSA株、 黄色ブドウ球菌を含む、。プラークサイズは、通常5〜15 mmの範囲であった。活動は、他の試験培養物（ 表1）に対して、見つかりませんでした。 S.の正常な成長球菌 ATCC 12600は37℃シェーカー·インキュベーターでNZY?...

Watch this Scientific Journal Video about Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria at JoVE.com

Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria

溶菌ファージバイオセンサーと抗体ビーズメチシリン耐性（MRSA）と敏感ブドウ球菌の細菌を区別することができます。ファージを水晶振動子マイクロバランスセンサーの表面上にラングミュア·ブロジェット法で固定し、広範囲のブドウ球菌プローブとして働いていた。抗体ビーズはMRSAを認識しています。

抗生物質耐性ブドウ球菌の細菌の検出のためのバイオセンサー

A structurally transformed lytic bacteriophage having a broad host range of Staphylococcus aureus strains and a penicillin-binding protein (PBP 2a) ...

biosensor-for-detection-antibiotic-resistant-staphylococcus

Research

JoVE Journal

Bioengineering

24.0K ビュー.  Auburn University. 溶菌ファージバイオセンサーと抗体ビーズメチシリン耐性（MRSA）と敏感ブドウ球菌の細菌を区別することができます。ファージを水晶振動子マイクロバランスセンサーの表面上にラングミュア·ブロジェット法で固定し、広範囲のブドウ球菌プローブとして働いていた。抗体ビーズはMRSAを認識しています。

ビデオ: Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria

Fluorescence detection methods for microfluidic droplet platforms

The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that accompany system miniaturisation. Advantages include the ability to efficiently process nano- to femoto- liter volumes of sample, facile integration of functional components, an intrinsic predisposition towards large-scale multiplexing, enhanced analytical throughput, improved control and reduced instrumental footprints.1
In recent years much interest has focussed on the development of droplet-based (or segmented flow) microfluidic systems and their potential as platforms in high-throughput experimentation.2-4 Here water-in-oil emulsions are made to spontaneously form in microfluidic channels as a result of capillary instabilities between the two immiscible phases. Importantly, microdroplets of precisely defined volumes and compositions can be generated at frequencies of several kHz. Furthermore, by encapsulating reagents of interest within isolated compartments separated by a continuous immiscible phase, both sample cross-talk and dispersion (diffusion- and Taylor-based) can be eliminated, which leads to minimal cross-contamination and the ability to time analytical processes with great accuracy. Additionally, since there is no contact between the contents of the droplets and the channel walls (which are wetted by the continuous phase) absorption and loss of reagents on the channel walls is prevented.
Once droplets of this kind have been generated and processed, it is necessary to extract the required analytical information. In this respect the detection method of choice should be rapid, provide high-sensitivity and low limits of detection, be applicable to a range of molecular species, be non-destructive and be able to be integrated with microfluidic devices in a facile manner. To address this need we have developed a suite of experimental tools and protocols that enable the extraction of large amounts of photophysical information from small-volume environments, and are applicable to the analysis of a wide range of physical, chemical and biological parameters. Herein two examples of these methods are presented and applied to the detection of single cells and the mapping of mixing processes inside picoliter-volume droplets. We report the entire experimental process including microfluidic chip fabrication, the optical setup and the process of droplet generation and detection.

Droplet-based microfluidic platforms are promising candidates for high throughput experimentation since they are able to generate picoliter, self-compartmentalized vessels inexpensively at kHz rates. Through integration with fast, sensitive and high resolution fluorescence spectroscopic methods, the large amounts of information generated within these systems can be efficiently extracted, harnessed and utilized.

マイクロ流体液滴のプラットフォームのための蛍光検出法

The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that ...

生物工学

Fabrication of Carbon Nanotube High-Frequency Nanoelectronic Biosensor for Sensing in High Ionic Strength Solutions

The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density5 in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded6-8.
We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers9-11. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies11-12. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier.
Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube13, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber14 onto the device, and (d) carry out high frequency sensing in different ionic strength solutions11.

We describe the device fabrication and measurement protocol for carbon nanotube based high frequency biosensors. The high frequency sensing technique mitigates the fundamental ionic (Debye) screening effect and allows nanotube biosensor to be operated in high ionic strength solutions where conventional electronic biosensors fail. Our technology provides a unique platform for point-of-care (POC) electronic biosensors operating in physiologically relevant conditions.

高イオン強度ソリューションで感知するためのカーボンナノチューブ高周波ナノエレクトロニクスバイオセンサーの作製

The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them ...

Optical Detection of E. coli Bacteria by Mesoporous Silicon Biosensors

A label-free optical biosensor based on a nanostructured porous Si is designed for rapid capture and detection of Escherichia coli K12 bacteria, as a model microorganism. The biosensor relies on direct binding of the target bacteria cells onto its surface, while no pretreatment (e.g.&#160;by cell lysis) of the studied sample is required. A mesoporous Si thin film is used as the optical transducer element of the biosensor. Under white light illumination, the porous layer displays well-resolved Fabry-P&#233;rot fringe patterns in its reflectivity spectrum. Applying a fast Fourier transform (FFT) to reflectivity data results in a single peak. Changes in the intensity of the FFT peak are monitored. Thus, target bacteria capture onto the biosensor surface, through antibody-antigen interactions, induces measurable changes in the intensity of the FFT peaks, allowing for a &#39;real time&#39; observation of bacteria attachment.
The mesoporous Si film, fabricated by an electrochemical anodization process, is conjugated with monoclonal antibodies, specific to the target bacteria. The immobilization, immunoactivity and specificity of the antibodies are confirmed by fluorescent labeling experiments. Once the biosensor is exposed to the target bacteria, the cells are directly captured onto the antibody-modified porous Si surface. These specific capturing events result in intensity changes in the thin-film optical interference spectrum of the biosensor. We demonstrate that these biosensors can detect relatively low bacteria concentrations (detection limit of 104 cells/ml) in less than an hour.

Optical Detection of E. coli Bacteria by Mesoporous Silicon Biosensors

A label-free optical biosensor for rapid bacteria detection is introduced. The biosensor is based on a nanostructured porous Si, which is designed to directly capture the target bacteria cells onto its surface. We use monoclonal antibodies, immobilized onto the porous transducer, as the capture probes. Our studies demonstrate the applicability of these biosensors for the detection of low bacterial concentrations within minutes with no prior sample processing (such as cell lysis).

を光学的に検出<em&gt; E.大腸菌の</emメソポーラスケイ素バイオセンサーによる&gt;バクテリア

A label-free optical biosensor based on a nanostructured porous Si is designed for rapid capture and detection of Escherichia coli K12 bacteria, as a ...

Stress-induced Antibiotic Susceptibility Testing on a Chip

We have developed a rapid microfluidic method for antibiotic susceptibility testing in a stress-based environment. Fluid is passed at high speeds over bacteria immobilized on the bottom of a microfluidic channel. In the presence of stress and antibiotic, susceptible strains of bacteria die rapidly. However, resistant bacteria survive these stressful conditions. The hypothesis behind this method is new: stress activation of biochemical pathways, which are targets of antibiotics, can accelerate antibiotic susceptibility testing. As compared to standard antibiotic susceptibility testing methods, the rate-limiting step -&#160;bacterial growth -&#160;is omitted during antibiotic application. The technical implementation of the method is in a combination of standard techniques and innovative approaches. The standard parts of the method include bacterial culture protocols, defining microfluidic channels in polydimethylsiloxane&#160;(PDMS), cell viability monitoring with fluorescence, and batch image processing for bacteria counting. Innovative parts of the method are in the use of culture media flow for mechanical stress application, use of enzymes to damage but not kill the bacteria, and use of microarray substrates for bacterial attachment. The developed platform can be used in antibiotic and nonantibiotic related drug development and testing. As compared to the standard bacterial suspension experiments, the effect of the drug can be turned on and off repeatedly over controlled time periods. Repetitive observation of the same bacterial population is possible over the course of the same experiment.

We have developed a microfluidic platform for rapid antibiotic susceptibility testing. Fluid is passed at high speeds over bacteria immobilized on the bottom of a microfluidic channel. In the presence of stress and antibiotic, susceptible strains of bacteria die rapidly. However, resistant bacteria can survive these stressful conditions.

チップ上でのストレス誘発抗生物質感受性試験

We have developed a rapid microfluidic method for antibiotic susceptibility testing in a stress-based environment. Fluid is passed at high speeds over ...

Sensitive Detection of Proteopathic Seeding Activity with FRET Flow Cytometry

Increasing evidence supports transcellular propagation of toxic protein aggregates, or proteopathic seeds, as a mechanism for the initiation and progression of pathology in several neurodegenerative diseases, including Alzheimer's disease and the related tauopathies. The potentially critical role of tau seeds in disease progression strongly supports the need for a sensitive assay that readily detects seeding activity in biological samples. 
By combining the specificity of fluorescence resonance energy transfer (FRET), the sensitivity of flow cytometry, and the stability of a monoclonal cell line, an ultra-sensitive seeding assay has been engineered and is compatible with seed detection from recombinant or biological samples, including human and mouse brain homogenates. The assay employs monoclonal HEK 293T cells that stably express the aggregation-prone repeat domain (RD) of tau harboring the disease-associated P301S mutation fused to either CFP or YFP, which produce a FRET signal upon protein aggregation. The uptake of proteopathic tau seeds (but not other proteins) into the biosensor cells stimulates aggregation of RD-CFP and RD-YFP, and flow cytometry sensitively and quantitatively monitors this aggregation-induced FRET. The assay detects femtomolar concentrations (monomer equivalent) of recombinant tau seeds, has a dynamic range spanning three orders of magnitude, and is compatible with brain homogenates from tauopathy transgenic mice and human tauopathy subjects. With slight modifications, the assay can also detect seeding activity of other proteopathic seeds, such as &#945;-synuclein, and is also compatible with primary neuronal cultures. The ease, sensitivity, and broad applicability of FRET flow cytometry makes it useful to study a wide range of protein aggregation disorders.

Cell-to-cell transfer of protein aggregates, or proteopathic seeds, may underlie the progression of pathology in neurodegenerative diseases. Here, a novel FRET flow cytometry assay is described that enables specific and sensitive detection of seeding activity from recombinant or biological samples.

FRETフローサイトメトリーでProteopathic播種活動の高感度検出

Increasing evidence supports transcellular propagation of toxic protein aggregates, or proteopathic seeds, as a mechanism for the initiation and ...

High-throughput Identification of Bacteria Repellent Polymers for Medical Devices

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as contributing to antimicrobial resistance. One possible avenue for the reduction of device-associated infections is the identification of bacteria-repellent polymer coatings for these devices, which would prevent bacterial binding at the initial attachment step. A method for the identification of such repellent polymers, based on the parallel screening of hundreds of polymers using a microarray, is described here. This high-throughput method resulted in the identification of a range of promising polymers that resisted binding of various clinically relevant bacterial species individually and also as multi-species communities. One polymer, PA13 (poly(methylmethacrylate-co-dimethylacrylamide)), demonstrated significant reduction in attachment of a number of hospital isolates when coated onto two commercially available central venous catheters. The method described could be applied to identify polymers for a wide range of applications in which modification of bacterial attachment is important.

A high-throughput microarray method for the identification of polymers which reduce bacterial surface binding on medical devices is described.

医療機器のための細菌撥ポリマーのハイスループット同定

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as ...

Microfluidic Platform with Multiplexed Electronic Detection for Spatial Tracking of Particles

Microfluidic processing of biological samples typically involves differential manipulations of suspended particles under various force fields in order to spatially fractionate the sample based on a biological property of interest. For the resultant spatial distribution to be used as the assay readout, microfluidic devices are often subjected to microscopic analysis requiring complex instrumentation with higher cost and reduced portability. To address this limitation, we have developed an integrated electronic sensing technology for multiplexed detection of particles at different locations on a microfluidic chip. Our technology, called Microfluidic CODES, combines Resistive Pulse Sensing with Code Division Multiple Access to compress 2D spatial information into a 1D electrical signal. In this paper, we present a practical demonstration of the Microfluidic CODES technology to detect and size cultured cancer cells distributed over multiple microfluidic channels. As validated by the high-speed microscopy, our technology can accurately analyze dense cell populations all electronically without the need for an external instrument. As such, the Microfluidic CODES can potentially enable low-cost integrated lab-on-a-chip devices that are well suited for the point-of-care testing of biological samples.

We demonstrate a microfluidic platform with an integrated surface electrode network that combines resistive pulse sensing (RPS) with code division multiple access (CDMA), to multiplex detection and sizing of particles in multiple microfluidic channels.

粒子の空間追跡のための多重化された電子の検出とマイクロ流体プラットフォーム

Microfluidic processing of biological samples typically involves differential manipulations of suspended particles under various force fields in order to ...

The Use of a &#946;-lactamase-based Conductimetric Biosensor Assay to Detect Biomolecular Interactions

Biosensors are becoming increasingly important and implemented in various fields such as pathogen detection, molecular diagnosis, environmental monitoring, and food safety control. In this context, we used &#946;-lactamases as efficient reporter enzymes in several protein-protein interaction studies. Furthermore, their ability to accept insertions of peptides or structured proteins/domains strongly encourages the use of these enzymes to generate chimeric proteins. In a recent study, we inserted a single-domain antibody fragment into the Bacillus licheniformis BlaP &#946;-lactamase. These small domains, also called nanobodies, are defined as the antigen-binding domains of single chain antibodies from camelids. Like common double chain antibodies, they show high affinities and specificities for their targets. The resulting chimeric protein exhibited a high affinity against its target while retaining the &#946;-lactamase activity. This suggests that the nanobody and &#946;-lactamase moieties remain functional. In the present work, we report a detailed protocol that combines our hybrid &#946;-lactamase system to the biosensor technology. The specific binding of the nanobody to its target can be detected thanks to a conductimetric measurement of the protons released by the catalytic activity of the enzyme.

In this work, we report a new method to study protein-protein interactions using a conductimetric biosensor based on the hybrid &#946;-lactamase technology. This method relies on release of protons upon hydrolysis of &#946;-lactams.

生体分子相互作用を検出する β-ラクタマーゼによる伝導度バイオ センサー法の使用

Biosensors are becoming increasingly important and implemented in various fields such as pathogen detection, molecular diagnosis, environmental ...

Development of an Electrochemical DNA Biosensor to Detect a Foodborne Pathogen

Vibrio parahaemolyticus (V. parahaemolyticus) is a common foodborne pathogen that contributes to a large proportion of public health problems globally, significantly affecting the rate of human mortality and morbidity. Conventional methods for the detection of V. parahaemolyticus such as culture-based methods, immunological assays, and molecular-based methods require complicated sample handling and are time-consuming, tedious, and costly. Recently, biosensors have proven to be a promising and comprehensive detection method with the advantages of fast detection, cost-effectiveness, and practicality. This research focuses on developing a rapid method of detecting V. parahaemolyticus with high selectivity and sensitivity using the principles of DNA hybridization. In the work, characterization of synthesized polylactic acid-stabilized gold nanoparticles (PLA-AuNPs) was achieved using X-ray Diffraction (XRD), Ultraviolet-visible Spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM), Field-emission Scanning Electron Microscopy (FESEM), and Cyclic Voltammetry (CV). We also carried out further testing of stability, sensitivity, and reproducibility of the PLA-AuNPs. We found that the PLA-AuNPs formed a sound structure of stabilized nanoparticles in aqueous solution. We also observed that the sensitivity improved as a result of the smaller charge transfer resistance (Rct) value and an increase of active surface area (0.41 cm2). The development of our DNA biosensor was based on modification of a screen-printed carbon electrode (SPCE) with PLA-AuNPs and using methylene blue (MB) as the redox indicator. We assessed the immobilization and hybridization events by differential pulse voltammetry (DPV). We found that complementary, non-complementary, and mismatched oligonucleotides were specifically distinguished by the fabricated biosensor. It also showed reliably sensitive detection in cross-reactivity studies against various food-borne pathogens and in the identification of V. parahaemolyticus in fresh cockles.

A protocol for the development of an electrochemical DNA biosensor comprising a polylactic acid-stabilized, gold nanoparticles-modified, screen-printed carbon electrode to detect Vibrio parahaemolyticus is presented.

食品由来病原体を検出する電気化学的 DNA のバイオ センサーの開発

Vibrio parahaemolyticus (V. parahaemolyticus) is a common foodborne pathogen that contributes to a large proportion of public health problems globally, ...

Visual Detection of Multiple Nucleic Acids in a Capillary Array

Multi-target, short time, and resource-affordable methodologies for the detection of multiple nucleic acids in a single, easy to operate test are urgently needed in disease diagnosis, microbial monitoring, genetically modified organism (GMO) detection, and forensic analysis. We have previously described the platform called CALM (Capillary Array-based Loop-mediated isothermal amplification for Multiplex visual detection of nucleic acids). Herein, we describe improved fabrication and performance processes for this platform. Here, we apply a small, ready-to-use cassette assembled by capillary array for multiplex visual detection of nucleic acids. The capillary array is pre-treated into a hydrophobic and hydrophilic pattern before fixing loop-mediated isothermal amplification (LAMP) primer sets in capillaries. After assembly of the loading adaptor, LAMP reaction mixture is loaded and isolated into each capillary, due to capillary force by a single pipetting step. The LAMP reactions are performed in parallel in the capillaries. The results are visually read out by illumination with a hand-held UV flashlight. Using this platform, we demonstrate monitoring of 8 frequently appearing elements and genes in GMO samples with high specificity and sensitivity. In summary, the platform described herein is intended to facilitate the detection of multiple nucleic acids. We believe it will be widely applicable in fields where high-throughput nucleic acid analysis is required.

This protocol describes the fabrication of a small, ready-to-use cassette that can be applied for visual detection of multiple nucleic acids in a single, test that is easy to operate. In this approach, a capillary array was used for multiplex and highly efficient detection of GMO targets.

キャピラリー配列で複数の核酸の視覚的検出

Multi-target, short time, and resource-affordable methodologies for the detection of multiple nucleic acids in a single, easy to operate test are urgently ...