Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)

Accurately detecting and counting sparse bacterial samples has many applications in the food, beverage, and pharmaceutical processing industries, in ...

California Institute of Technology

Hippocampal neurons.

The photophysical properties of CdSe and ZnS(CdSe) semiconductor quantum dots in nonpolar and aqueous solutions were examined with steady-state (absorption and emission) and time-resolved (time-correlated single-photon-counting) spectroscopy. The CdSe structures were prepared from a single CdSe synthesis, a portion of which were ZnS-capped, thus any differences observed in the spectral behavior between the two preparations were due to changes in the molecular shell. Quantum dots in nonpolar solvents were surrounded with a trioctylphosphine oxide (TOPO) coating from the initial synthesis solution. ZnS-capped CdSe were initially brighter than bare uncapped CdSe and had overall faster emission decays. The dynamics did not vary when the solvent was changed from hexane to dichloromethane; however, replacement of the TOPO cap by pyridine affected CdSe but not ZnS(CdSe). CdSe was then solubilized in water with mercapto-acetic acid or dihydrolipoic acid, whereas ZnS(CdSe) could be solubilized only with dihydrolipoic acid. Both solubilization agents quenched the nanocrystal emission, though with CdSe the quenching was nearly complete. Additional quenching of the remaining emission was observed when the redox-active molecule adenine was conjugated to the water-soluble CdSe but was not seen with ZnS(CdSe). The emission of aqueous CdSe could be enhanced under prolonged exposure to room light and resulted in a substantial increase of the emission lifetimes; however, the enhancement occurred concurrently with precipitation of the nanocrystals, which was possibly caused by photocatalytic destruction of the mercaptoacetic acid coating. These results are the first presented on aqueous CdSe quantum dot structures and are presented in the context of designing better, more stable biological probes.

Photophysical properties of biologically compatible CdSe quantum dot structures.

&#x7845;&#x7247;&#x7684;&#x516B;&#x4E2A;&#x5355;&#x72EC;&#x53EF;&#x5BFB;&#x5740;&#x8D85;&#x5FAE;&#x578B;&#x5B54;&#x7528;&#x4E8E;&#x79BB;&#x5B50;&#x901A;&#x9053;&#x91CD;&#x6784;&#x548C;&#x5355;&#x901A;&#x9053;&#x5F55;&#x97F3;&#x3002;&#x81EA;&#x65CB;&#x5BF9;&#x542B;&#x6C1F;&#x805A;&#x5408;&#x7269;&#x521B;&#x5EFA;&#x4E86;&#x6BD4;&#x7845;&#x70F7;&#x66F4;&#x7A33;&#x5B9A;&#x7684;&#x7EDD;&#x7F18;&#x3001; &#x758F;&#x6C34;&#x63A5;&#x53E3;&#x3002;&#x603B;&#x7535;&#x5BB9;&#x7684;&#x819C;&#x662F; &lt; 10 pF&#xFF0C;&#x4F7F;&#x5B83;&#x6613;&#x4E8E;&#x7535;&#x5BB9;&#x53D8;&#x5316;&#x4E2D; 50-250 microm &#x76F4;&#x5F84;&#x5B54;&#x7684;&#x6613;&#x7528;&#x6027;&#x548C;&#x7A33;&#x5B9A;&#x6027;&#x7684;&#x53CC;&#x5C42;&#x5F62;&#x6210; &#xFF1B; &#x8FDB;&#x884C;&#x4E86;&#x6D4B;&#x8BD5;&#xFF0C;&#x6765;&#x8BC4;&#x4F30;&#x53CC;&#x5C42;&#x5F62;&#x6210;&#x53EA;&#x6709;&#x90A3;&#x4E9B; &gt; 100 microm &#x5BFC;&#x81F4;&#x79BB;&#x5B50;&#x901A;&#x9053;&#x529F;&#x80FD;&#x3002;&#x53CC;&#x5C42;&#x88AB;&#x5F62;&#x6210;&#x652F;&#x6301;&#x5C42;&#x743C;&#x8102;&#x7CD6;&#x8102;&#x8D28;&#x5728;&#x7528;&#x753B;&#x7B14; &#xFF1B; decane &#x7684;&#x5E94;&#x7528;&#x7A0B;&#x5E8F;&#x7136;&#x540E;&#x53EF;&#x4EE5;&#x6DFB;&#x52A0;&#x7B2C;&#x4E8C;&#x5C42;&#x7684;&#x743C;&#x8102;&#x7CD6;&#x7A33;&#x5B9A;&#x7ED3;&#x6784;&#x548C;&#x9632;&#x6B62;&#x84B8;&#x53D1;&#x3002;&#x5FAE;&#x6D41;&#x63A7;&#x4E95;&#x5EFA;&#x73BB;&#x7483;&#x677F;&#x6750;&#x6613;&#x4E8E;&#x7EC4;&#x88C5;&#x548C;&#x53EF;&#x89C6;&#x5316;&#x7684;&#x6D41;&#x4F53;&#x7684;&#x6D41;&#x52A8;&#xFF0C;&#x4EE5;&#x53CA;&#x9AD8;&#x5206;&#x8FA8;&#x7387;&#x663E;&#x5FAE;&#x955C;&#x7814;&#x7A76;&#x5229;&#x7528;&#x8367;&#x5149;&#x8840;&#x8102;&#x548C;&#x6E20;&#x9053;&#x3002;&#x5FAE;&#x6D41;&#x4F53;&#x5305;&#x62EC;&#x53EF;&#x9006;&#x4FDD;&#x7A0E;&#x7684;&#x7845;&#x6A61;&#x80F6; (PDMS)&#xFF0C;&#x4ECE;&#x800C;&#x4F7F;&#x6574;&#x4E2A;&#x8BBE;&#x5907;&#x80FD;&#x591F;&#x6D17;&#x51C0;&#x5E76;&#x91CD;&#x7528;&#x3002;&#x603B;&#x7535;&#x6C14;&#x566A;&#x58F0;&#x7684;&#x8BBE;&#x5907;&#x662F;&#x8DB3;&#x591F;&#x4F4E;&#xFF0C;&#x4EE5;&#x4FBF;&#x5141;&#x8BB8;&#x5355;&#x901A;&#x9053;&#x7684;&#x51B3;&#x8BAE;&#x3002;&#x6210;&#x529F;&#x901A;&#x9053;&#x63D2;&#x5165;&#x4E86;&#x89C2;&#x5BDF;&#x4E0E;&#x81EA;&#x6211;&#x7EC4;&#x88C5;&#x7684;&#x79BB;&#x5B50;&#x8F7D;&#x4F53; (alamethicin) &#x4EE5;&#x53CA;&#x590D;&#x6742;&#x3001; &#x56CA;&#x6CE1;&#x5173;&#x8054;&#x7684;&#x54FA;&#x4E73;&#x52A8;&#x7269;&#x901A;&#x9053; &#xFF08;&#x4EBA;&#x7C7B;&#x7518;&#x6C28;&#x9178;&#x53D7;&#x4F53;&#xFF0C;GlyR&#xFF09;&#x3002;&#x6B64;&#x5916;&#x6D4B;&#x8BD5;&#x53CC;&#x5C42;&#x5F62;&#x6210;&#x4E00;&#x79CD;&quot;&#x514D;&#x63D0;&#x5F0F;&quot;&#x65B9;&#x6CD5;&#xFF0C;&#x6EB6;&#x5242;&#x4E2D;&#x7684;&#x8102;&#x8D28;&#x662F;&#x901A;&#x8FC7;&#x65CB;&#x8F6C;&#x6D82;&#x5C42;&#x5E94;&#x7528;&#x4E8E;&#x6676;&#x5706;&#x7247;&#x3001; &#x6652;&#x5E72;&#xFF0C;&#x7136;&#x540E;&quot;&#x4E09;&#x660E;&#x6CBB;&quot;&#x7684;&#x743C;&#x8102;&#x7CD6;&#x4E0A;&#x9762;&#x548C;&#x4E0B;&#x9762;&#x7684;&#x6C2E;&#x5316;&#x5C42;&#x4E4B;&#x95F4;&#x3002;&#x7535;&#x6C14;&#x6027;&#x80FD;&#x7B26;&#x5408;&#x53CC;&#x5C42;&#x53D1;&#x73B0;&#x548C;&#x83B7;&#x5F97;&#x4E86; alamethicin &#x5F55;&#x97F3;&#xFF0C;&#x4F46;&#x662F;&#x6B64;&#x65B9;&#x6CD5;&#x4E0D;&#x517C;&#x5BB9;&#x4E0E;&#x56CA;&#x6CE1;&#x542B;&#x54FA;&#x4E73;&#x52A8;&#x7269;&#x6E20;&#x9053;&#x7684;&#x878D;&#x5408;&#x3002;

&#x91CD;&#x6784;&#x7684;&#x79BB;&#x5B50;&#x901A;&#x9053;&#x5728;&#x743C;&#x8102;&#x7CD6;&#x652F;&#x6301;&#x7845;&#x7A8D;&#x3002;

A silicon wafer with eight individually addressable microfabricated orifices was used for ion channel reconstitution and single-channel recording. A spin-on fluoropolymer created an insulating, hydrophobic interface that was more stable than silane. Total capacitance of the membranes was <10 pF, making it easy to evaluate bilayer formation by capacitance change. Orifices of 50-250 microm diameter were tested for ease and stability of bilayer formation; only those >100 microm resulted in ion channel function. Bilayers were formed over an agarose supporting layer by application of lipid in decane with a paintbrush; a second layer of agarose could then be added to stabilize the structure and prevent evaporation. Microfluidic wells were constructed on glass plates for ease of assembly and visualization of fluid flow, as well as high-resolution microscopy for studies using fluorescent lipids and channels. The microfluidics consisted of reversibly bonded silicone rubber (PDMS), so that the entire device could be washed and reused. Total electrical noise in the device was low enough to permit single-channel resolution. Successful channel insertions were observed with a self-assembling ionophore (alamethicin) as well as a complex, vesicle-associated mammalian channel (human glycine receptor, GlyR). A "hands-free" approach to bilayer formation was also tested, where lipid in solvent was applied to the wafer by spin-coating, dried, and then "sandwiched" between layers of agarose above and below the nitride. Electrical properties consistent with bilayers were observed and alamethicin recordings were obtained, however this method is not compatible with the fusion of vesicles containing mammalian channels.

Reconstitution of ion channels in agarose-supported silicon orifices.

Une plaquette de silicium avec huit orifices adressables individuellement microfabriqu&#xE9;s est utilis&#xE9;e pour la reconstitution de canal ionique et un seul canal d&#x26;#39;enregistrement. Un spin-sur fluoropolym&#xE8;re cr&#xE9;&#xE9; un isolant, l&#x26;#39;interface hydrophobe qui a &#xE9;t&#xE9; plus stable que le silane. La capacit&#xE9; totale des membranes &#xE9;tait &#x26;lt;10 pF, ce qui rend facile &#xE0; &#xE9;valuer la formation bicouche par le changement de capacit&#xE9;. Les orifices de diam&#xE8;tre de 50-250 microm&#xE8;tre ont &#xE9;t&#xE9; test&#xE9;s pour la facilit&#xE9; et la stabilit&#xE9; de la formation bicouche, seulement ceux&#x26;gt; 100 microm abouti &#xE0; la fonction du canal ionique. Bicouches sont form&#xE9;es sur une couche d&#x26;#39;agarose support par application de lipide dans le d&#xE9;cane avec un pinceau, une deuxi&#xE8;me couche d&#x26;#39;agarose peut ensuite &#xEA;tre ajout&#xE9; &#xE0; stabiliser la structure et emp&#xEA;cher l&#x26;#39;&#xE9;vaporation. Microfluidique puits ont &#xE9;t&#xE9; construits sur des plaques de verre pour faciliter l&#x26;#39;assemblage et la visualisation de l&#x26;#39;&#xE9;coulement du fluide, ainsi que microscopie &#xE0; haute r&#xE9;solution pour les &#xE9;tudes utilisant des lipides fluorescents et des canaux. Les microfluidique compos&#xE9; de caoutchouc de silicone de fa&#xE7;on r&#xE9;versible li&#xE9; (PDMS), de telle sorte que l&#x26;#39;ensemble du dispositif peut &#xEA;tre lav&#xE9; et r&#xE9;utilis&#xE9;. Totale de bruit &#xE9;lectrique dans le dispositif &#xE9;tait suffisamment faible pour permettre &#xE0; canal unique de r&#xE9;solution. Insertions de canal re&#xE7;us ont &#xE9;t&#xE9; observ&#xE9;e avec un ionophore auto-assemblante (alam&#xE9;thicine) ainsi que d&#x26;#39;un complexe, des v&#xE9;sicules canal associ&#xE9; mammif&#xE8;re (humaine glycine r&#xE9;cepteur, GlyR). Un &#xAB;mains libres&#xBB; en mati&#xE8;re de formation bicouche a &#xE9;galement &#xE9;t&#xE9; test&#xE9;, o&#xF9; des lipides dans un solvant a &#xE9;t&#xE9; appliqu&#xE9; &#xE0; la tranche par spin-coating, s&#xE9;ch&#xE9;, puis en &#x26;quot;sandwich&#x26;quot; entre les couches d&#x26;#39;agarose ci-dessus et en dessous du nitrure. Les propri&#xE9;t&#xE9;s &#xE9;lectriques compatibles avec les bicouches ont &#xE9;t&#xE9; observ&#xE9;s et les enregistrements ont &#xE9;t&#xE9; obtenus alam&#xE9;thicine, mais cette m&#xE9;thode n&#x26;#39;est pas compatible avec la fusion des v&#xE9;sicules contenant des canaux de mammif&#xE8;res.

Reconstitution des canaux ioniques dans des orifices de silicium Agarose soutenus par

Eine Silizium-Wafer mit acht einzeln adressierbare Microfabricated &Ouml;ffnungen wurde f&uuml;r Einkanal-Aufnahme und Ion Kanal Rekonstitution verwendet. Ein Spin-on Fluorpolymer erstellt eine isolierende, Hydrophobe Oberfl&auml;che, die stabiler als Silan war. Gesamt Kapazit&auml;t der Membranen wurde &lt; 10 pF, erleichtert das auswerten Bilayer bildung kapazitiv &auml;ndern. K&ouml;rper&ouml;ffnungen 50-250 Microm durchmesser f&uuml;r leichtigkeit und stabilit&auml;t Bilayer-formation; getestet wurden nur diejenigen &gt; 100 Microm resultierte in Ionen-Kanal-Funktion. Doppelschichten bildeten sich durch Anwendung von Lipid in Decan mit einem Pinsel &uuml;ber eine Agarose Schicht zu unterst&uuml;tzen; eine zweite Schicht Agarose konnte dann hinzugef&uuml;gt werden, stabilisieren die Struktur und Verdunstung zu verhindern. Mikrofluidische Brunnen wurden auf Glasplatten f&uuml;r einfache Montage und Visualisierung der Fl&uuml;ssigkeitsstr&ouml;mung sowie hochaufl&ouml;sende Mikroskopie f&uuml;r Studien mit fluoreszierenden Lipiden und Kan&auml;le gebaut. Die Mikrofluidik bestand umkehrbar geklebte Silikonkautschuk (PDMS), so dass das gesamte Ger&auml;t gewaschen und wiederverwendet werden konnte. Gesamt elektrisches Rauschen im Ger&auml;t war niedrig genug, um Einkanal-Aufl&ouml;sung zu erm&ouml;glichen. Erfolgreiche Kanal Einf&uuml;gungen wurden mit einem selbstorganisierende Ionophor (Alamethicin) sowie einen komplexen, Vesikel-assoziiertes S&auml;ugetier-Kanal (menschliche Glycin-Rezeptor, GlyR) beobachtet. Ein &quot;Hands-free&quot; Ansatz Bilayer-Formation wurde auch getestet, wo Lipid in L&ouml;sungsmittel wurde angewandt auf den Wafer durch Spin-Coating, getrocknet und dann &quot;eingequetscht&quot; zwischen Schichten von Agarose oben und unten das Nitrid. Einklang mit Doppelschichten elektrische Eigenschaften wurden beobachtet und Alamethicin Aufnahmen wurden erzielt, diese Methode ist jedoch nicht kompatibel mit der Fusion von Vesikeln, S&auml;ugetier-Kan&auml;le enth&auml;lt.

Rekonstitution von Ionenkan&auml;len in Agarose-unterst&uuml;tzte Silizium K&ouml;rper&ouml;ffnungen.

Un wafer di silicio con otto microfabricated individualmente indirizzabili orifizi &egrave; stato utilizzato per la ricostituzione del canale ionico e registrazione monocanale. Un fluoropolimero spin-on creato un&#39;interfaccia isolante, idrorepellente che era pi&ugrave; stabile rispetto silani. Capacit&agrave; totale delle membrane &egrave; stato &lt; pF 10, rendendo pi&ugrave; semplice valutare la formazione di doppio strato di capacitanza cambiamento. orifizi del diametro di 50-250 microm sono stati testati per la facilit&agrave; e la stabilit&agrave; della formazione del doppio strato; solo quelli &amp;gt; 100 microm portato in funzione dei canali ionici. Bilayer si formarono sopra un&#39;agarosi strato di supporto di applicazione di lipidi in decano (idrocarburo) con un pennello; un secondo strato di agarosio potrebbe quindi essere aggiunto per stabilizzare la struttura e prevenire l&#39;evaporazione. Microfluidica pozzi sono stati costruiti su lastre di vetro per la facilit&agrave; di montaggio e visualizzazione del flusso del fluido, cos&igrave; come la microscopia ad alta risoluzione per gli studi che utilizzano canali e lipidi fluorescente. La microfluidica consisteva reversibilmente legato gomma di silicone (PDMS), cos&igrave; che l&#39;intero dispositivo potrebbe essere lavato e riutilizzato. Rumore elettrico totale nel dispositivo era abbastanza basso per consentire la risoluzione del singolo canale. Inserimenti di successo del canale sono stati osservati con un auto-assemblanti ionoforo (alamethicin) cos&igrave; come un complesso, vescicola-associato canale dei mammiferi (recettore umano glicina, GlyR). &Egrave; stato testato anche un approccio &quot;hands-free&quot; per la formazione del doppio strato, dove lipidi in solvente era applicato a wafer di spin-coating, essiccato e poi &quot;sandwich&quot; tra strati di agarosio sopra e sotto il nitruro. Sono state osservate propriet&agrave; elettriche coerenti con bilayer e alamethicin registrazioni sono stati ottenuti, tuttavia questo metodo non &egrave; compatibile con la fusione delle vescicole contenenti canali dei mammiferi.

Ricostituzione dei canali ionici in orifizi silicio supportati da agarosi.

8&#x500B;&#x3005;&#x306B;&#x30A2;&#x30C9;&#x30EC;&#x30B9;&#x53EF;&#x80FD;&#x306A;&#x5FAE;&#x7D30;&#x52A0;&#x5DE5;&#x30AA;&#x30EA;&#x30D5;&#x30A3;&#x30B9;&#x3092;&#x6709;&#x3059;&#x308B;&#x30B7;&#x30EA;&#x30B3;&#x30F3;&#x30A6;&#x30A7;&#x30FC;&#x30CF;&#x306F;&#x3001;&#x30A4;&#x30AA;&#x30F3;&#x30C1;&#x30E3;&#x30CD;&#x30EB;&#x306E;&#x518D;&#x69CB;&#x6210;&#x3068;&#x30B7;&#x30F3;&#x30B0;&#x30EB;&#x30C1;&#x30E3;&#x30F3;&#x30CD;&#x30EB;&#x306E;&#x8A18;&#x9332;&#x306B;&#x4F7F;&#x7528;&#x3055;&#x308C;&#x305F;&#x3002;&#x30B9;&#x30D4;&#x30F3;&#x30AA;&#x30F3;&#x30D5;&#x30EB;&#x30AA;&#x30ED;&#x30DD;&#x30EA;&#x30DE;&#x30FC;&#x306F;&#x3001;&#x30B7;&#x30E9;&#x30F3;&#x3088;&#x308A;&#x3082;&#x5B89;&#x5B9A;&#x3067;&#x3042;&#x3063;&#x305F;&#x7D76;&#x7E01;&#x3001;&#x758E;&#x6C34;&#x6027;&#x306E;&#x30A4;&#x30F3;&#x30BF;&#x30FC;&#x30D5;&#x30A7;&#x30A4;&#x30B9;&#x3092;&#x4F5C;&#x6210;&#x3057;&#x307E;&#x3057;&#x305F;&#x3002;&#x819C;&#x306E;&#x7DCF;&#x5BB9;&#x91CF;&#x306F;&#x3001;&#x7C21;&#x5358;&#x306B;&#x5BB9;&#x91CF;&#x306E;&#x5909;&#x5316;&#x306B;&#x3088;&#x308B;&#x4E8C;&#x91CD;&#x5C64;&#x306E;&#x5F62;&#x6210;&#x3092;&#x8A55;&#x4FA1;&#x3059;&#x308B;&#x3053;&#x3068;&#x3001;&#x26;lt;10 pF&#x306E;&#x3067;&#x3057;&#x305F;&#x3002; 50&#x304B;&#x3089;250&#x30DE;&#x30A4;&#x30AF;&#x30ED;&#x30E2;&#x30EB;&#x5F84;&#x306E;&#x30AA;&#x30EA;&#x30D5;&#x30A3;&#x30B9;&#x306F;&#x3001;&#x4E8C;&#x91CD;&#x5C64;&#x306E;&#x5F62;&#x6210;&#x306E;&#x3057;&#x3084;&#x3059;&#x3055;&#x3068;&#x5B89;&#x5B9A;&#x6027;&#x3092;&#x8A66;&#x9A13;&#x3057;&#x305F;&#x3002;&#x306E;&#x307F;&#x26;gt; 100&#x30DE;&#x30A4;&#x30AF;&#x30ED;&#x30E2;&#x30EB;&#x3001;&#x30A4;&#x30AA;&#x30F3;&#x30C1;&#x30E3;&#x30CD;&#x30EB;&#x306E;&#x6A5F;&#x80FD;&#x3068;&#x306A;&#x308A;&#x307E;&#x3057;&#x305F;&#x3002;&#x4E8C;&#x91CD;&#x5C64;&#x306F;&#x3001;&#x7D75;&#x7B46;&#x3068;&#x30C7;&#x30AB;&#x30F3;&#x306E;&#x8102;&#x8CEA;&#x306E;&#x30A2;&#x30D7;&#x30EA;&#x30B1;&#x30FC;&#x30B7;&#x30E7;&#x30F3;&#x306B;&#x3088;&#x3063;&#x3066;&#x30A2;&#x30AC;&#x30ED;&#x30FC;&#x30B9;&#x652F;&#x6301;&#x5C64;&#x4E0A;&#x306B;&#x5F62;&#x6210;&#x3055;&#x308C;&#x305F;;&#x30A2;&#x30AC;&#x30ED;&#x30FC;&#x30B9;&#x306E;&#x7B2C;&#x4E8C;&#x306E;&#x5C64;&#x306F;&#x3001;&#x305D;&#x306E;&#x69CB;&#x9020;&#x3092;&#x5B89;&#x5B9A;&#x5316;&#x3055;&#x305B;&#x3001;&#x84B8;&#x767A;&#x3092;&#x9632;&#x3050;&#x305F;&#x3081;&#x306B;&#x8FFD;&#x52A0;&#x3059;&#x308B;&#x3053;&#x3068;&#x304C;&#x3067;&#x304D;&#x307E;&#x3059;&#x3002;&#x30DE;&#x30A4;&#x30AF;&#x30ED;&#x6D41;&#x4F53;&#x306E;&#x4E95;&#x6238;&#x306F;&#x3001;&#x6D41;&#x4F53;&#x306E;&#x6D41;&#x308C;&#x3068;&#x540C;&#x69D8;&#x306B;&#x3001;&#x86CD;&#x5149;&#x8102;&#x8CEA;&#x304A;&#x3088;&#x3073;&#x30C1;&#x30E3;&#x30CD;&#x30EB;&#x3092;&#x7528;&#x3044;&#x305F;&#x7814;&#x7A76;&#x7528;&#x306E;&#x9AD8;&#x5206;&#x89E3;&#x80FD;&#x9855;&#x5FAE;&#x93E1;&#x306E;&#x7D44;&#x307F;&#x7ACB;&#x3066;&#x3068;&#x53EF;&#x8996;&#x5316;&#x3092;&#x5BB9;&#x6613;&#x306B;&#x3059;&#x308B;&#x305F;&#x3081;&#x306B;&#x30AC;&#x30E9;&#x30B9;&#x677F;&#x4E0A;&#x306B;&#x69CB;&#x7BC9;&#x3057;&#x305F;&#x3002;&#x30DE;&#x30A4;&#x30AF;&#x30ED;&#x6D41;&#x4F53;&#x30C7;&#x30D0;&#x30A4;&#x30B9;&#x5168;&#x4F53;&#x3092;&#x6D17;&#x6D44;&#x3057;&#x3001;&#x518D;&#x5229;&#x7528;&#x3067;&#x304D;&#x308B;&#x3088;&#x3046;&#x306B;&#x3001;&#x53EF;&#x9006;&#x7684;&#x306B;&#x7D50;&#x5408;&#x3057;&#x305F;&#x30B7;&#x30EA;&#x30B3;&#x30FC;&#x30F3;&#x30B4;&#x30E0;&#xFF08;PDMS&#xFF09;&#x304B;&#x3089;&#x6210;&#x3063;&#x3066;&#x3044;&#x305F;&#x3002;&#x30C7;&#x30D0;&#x30A4;&#x30B9;&#x306E;&#x7DCF;&#x96FB;&#x6C17;&#x7684;&#x306A;&#x30CE;&#x30A4;&#x30BA;&#x306F;&#x3001;&#x30B7;&#x30F3;&#x30B0;&#x30EB;&#x30C1;&#x30E3;&#x30CD;&#x30EB;&#x306E;&#x5206;&#x89E3;&#x80FD;&#x3092;&#x53EF;&#x80FD;&#x306B;&#x3059;&#x308B;&#x305F;&#x3081;&#x306B;&#x5341;&#x5206;&#x306B;&#x4F4E;&#x304B;&#x3063;&#x305F;&#x3002;&#x6210;&#x529F;&#x3057;&#x305F;&#x30C1;&#x30E3;&#x30CD;&#x30EB;&#x306E;&#x633F;&#x5165;&#x306F;&#x3001;&#x81EA;&#x5DF1;&#x7D44;&#x7E54;&#x5316;&#x30A4;&#x30AA;&#x30CE;&#x30D5;&#x30A9;&#x30A2;&#xFF08;&#x30A2;&#x30E9;&#x30E1;&#x30C1;&#x30B7;&#x30F3;&#xFF09;&#x3068;&#x540C;&#x69D8;&#x306B;&#x3001;&#x8907;&#x96D1;&#x306A;&#x5C0F;&#x80DE;&#x95A2;&#x9023;&#x54FA;&#x4E73;&#x985E;&#x306E;&#x30C1;&#x30E3;&#x30F3;&#x30CD;&#x30EB;&#xFF08;&#x30D2;&#x30C8;&#x30B0;&#x30EA;&#x30B7;&#x30F3;&#x53D7;&#x5BB9;&#x4F53;&#x3001;GlyR&#xFF09;&#x3067;&#x89B3;&#x5BDF;&#x3057;&#x305F;&#x3002;&#x4E8C;&#x91CD;&#x5C64;&#x306E;&#x5F62;&#x6210;&#x3078;&#x306E; &#x26;quot;&#x30CF;&#x30F3;&#x30BA;&#x30D5;&#x30EA;&#x30FC;&#x26;quot;&#x306E;&#x30A2;&#x30D7;&#x30ED;&#x30FC;&#x30C1;&#x306F;&#x307E;&#x305F;&#x3001;&#x6EB6;&#x5A92;&#x4E2D;&#x306E;&#x8102;&#x8CEA;&#x3092;&#x4E7E;&#x71E5;&#x3055;&#x305B;&#x3001;&#x30B9;&#x30D4;&#x30F3;&#x30B3;&#x30FC;&#x30C6;&#x30A3;&#x30F3;&#x30B0;&#x306B;&#x3088;&#x3063;&#x3066;&#x30A6;&#x30A7;&#x30FC;&#x30CF;&#x306B;&#x9069;&#x7528;&#x3057;&#x3001;&#x7A92;&#x5316;&#x7269;&#x306E;&#x4E0A;&#x4E0B;&#x30A2;&#x30AC;&#x30ED;&#x30FC;&#x30B9;&#x306E;&#x5C64;&#x306E;&#x9593;&#x306B; &#x26;quot;&#x631F;&#x307E;&#x308C;&#x305F;&#x26;quot;&#x3053;&#x3053;&#x3067;&#x3001;&#x30C6;&#x30B9;&#x30C8;&#x3055;&#x308C;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x4E8C;&#x91CD;&#x5C64;&#x3068;&#x4E00;&#x81F4;&#x3057;&#x3066;&#x96FB;&#x6C17;&#x7279;&#x6027;&#x304C;&#x89B3;&#x5BDF;&#x3055;&#x308C;&#x305F;&#x3068;&#x30A2;&#x30E9;&#x30E1;&#x30C1;&#x30B7;&#x30F3;&#x8A18;&#x9332;&#x304C;&#x5F97;&#x3089;&#x308C;&#x305F;&#x3001;&#x3057;&#x304B;&#x3057;&#x3001;&#x3053;&#x306E;&#x65B9;&#x6CD5;&#x306F;&#x3001;&#x54FA;&#x4E73;&#x52D5;&#x7269;&#x306E;&#x30C1;&#x30E3;&#x30F3;&#x30CD;&#x30EB;&#x3092;&#x542B;&#x3080;&#x5C0F;&#x80DE;&#x306E;&#x878D;&#x5408;&#x3068;&#x4E92;&#x63DB;&#x6027;&#x304C;&#x3042;&#x308A;&#x307E;&#x305B;&#x3093;&#x3002;

&#x30A2;&#x30AC;&#x30ED;&#x30FC;&#x30B9;&#x3067;&#x30B5;&#x30DD;&#x30FC;&#x30C8;&#x3055;&#x308C;&#x3066;&#x3044;&#x308B;&#x30B7;&#x30EA;&#x30B3;&#x30F3;&#x30AA;&#x30EA;&#x30D5;&#x30A3;&#x30B9;&#x306E;&#x30A4;&#x30AA;&#x30F3;&#x30C1;&#x30E3;&#x30CD;&#x30EB;&#x306E;&#x518D;&#x69CB;&#x6210;

8 &#xAC1C;&#xC758; &#xAC1C;&#xBCC4; &#xC5B4;&#xB4DC;&#xB808;&#xC2A4; &#xC9C0;&#xC815; &#xAC00;&#xB2A5; &#xFE59; orifices&#xC640; &#xC2E4;&#xB9AC;&#xCF58; &#xC6E8;&#xC774;&#xD37C;&#xB294; &#xC774;&#xC628; &#xCC44;&#xB110; &#xC7AC;&#xAD6C;&#xC131; &#xBC0F; &#xB2E8;&#xC77C; &#xCC44;&#xB110; &#xB179;&#xD654;&#xC5D0; &#xC0AC;&#xC6A9; &#xB418;&#xC5C8;&#xB2E4;. &#xC2A4;&#xD540;-&#xC628; &#xD50C;&#xB77C;&#xC2A4;&#xD2F1; silane &#xBCF4;&#xB2E4; &#xB354; &#xC548;&#xC815; &#xB41C; &#xB2E8; &#xC5F4;, &#xC18C;&#xC218; &#xC778;&#xD130;&#xD398;&#xC774;&#xC2A4;&#xB97C; &#xB9CC;&#xB4E4;&#xC5C8;&#xC2B5;&#xB2C8;&#xB2E4;. &#xC138;&#xD3EC; &#xB9C9;&#xC758; &#xCD1D; &#xCEE4;&#xD328;&#xC2DC;&#xD134;&#xC2A4;&#xB294; &lt; 10pf &#xCEE4;&#xD328;&#xC2DC;&#xD134;&#xC2A4; &#xBCC0;&#xD654;. 50-250 microm &#xC9C1;&#xACBD; Orifices &#xC27D;&#xACE0; bilayer &#xD615;&#xC131;;&#xC758; &#xC548;&#xC815;&#xC131;&#xC5D0; &#xB300; &#xD55C; &#xD14C;&#xC2A4;&#xD2B8;&#xB97C; &#xD588;&#xB2E4; &#xD558; &#xC5EC; bilayer &#xD615;&#xC131; &#xD3C9;&#xAC00;&#xB97C; &#xC27D;&#xAC8C; &#xB4E4;&#xB9CC; &amp;gt; 100 microm &#xADC0;&#xCC29;&#xB418; &#xC5C8; &#xB2E4; &#xC774;&#xC628; &#xCC44;&#xB110; &#xAE30;&#xB2A5;. Bilayers &#xC9C0;&#xC9C8; &#xBD93;;&#xC640; decane&#xC5D0;&#xC758; &#xC751;&#xC6A9; &#xD504;&#xB85C;&#xADF8;&#xB7A8;&#xC5D0;&#xC11C; &#xC9C0; &#xC6D0;&#xD558;&#xB294; &#xB808;&#xC774;&#xC5B4;&#xB294; agarose&#xB97C; &#xD1B5;&#xD574; &#xD615;&#xC131; &#xB418;&#xC5C8;&#xB2E4; agarose&#xC758; &#xB450; &#xBC88;&#xC9F8; &#xB808;&#xC774;&#xC5B4;&#xB294; &#xAD6C;&#xC870;&#xB97C; &#xC548;&#xC815;&#xD654; &#xD558; &#xACE0; &#xC99D;&#xBC1C; &#xBC29;&#xC9C0;&#xB97C; &#xCD94;&#xAC00;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;. &#xBBF8;&#xC138; &#xC2A4; &#xACE0;&#xD574;&#xC0C1;&#xB3C4; &#xD604;&#xBBF8;&#xACBD; &#xD615;&#xAD11; &#xC9C0;&#xC9C8;&#xACFC; &#xCC44;&#xB110;&#xC744; &#xC0AC;&#xC6A9; &#xD558; &#xC5EC; &#xC5F0;&#xAD6C;&#xC5D0; &#xB300; &#xD55C; &#xC5B4;&#xC148;&#xBE14;&#xB9AC; &#xC27D;&#xACE0; &#xC720;&#xCCB4; &#xD750;&#xB984;&#xC758; &#xC2DC;&#xAC01;&#xD654;&#xB97C; &#xC704;&#xD574; &#xC720;&#xB9AC; &#xC811;&#xC2DC;&#xC5D0; &#xAC74;&#xC124; &#xB418;&#xC5C8;&#xB2E4;. &#xC804;&#xCCB4; &#xC7A5;&#xCE58;&#xB97C; &#xC138;&#xCC99; &#xD558; &#xACE0; &#xB2E4;&#xC2DC; &#xC218;&#xB97C; microfluidics &#xC5ED; &#xBCF4; &#xC138; &#xC2E4;&#xB9AC;&#xCF58; &#xACE0;&#xBB34; (PDMS)&#xC758; &#xAD6C;&#xC131; &#xB418;&#xC5B4;&#xC788;&#xC2B5;&#xB2C8;&#xB2E4;. &#xCD1D; &#xC804;&#xAE30; &#xC7A1;&#xC74C; &#xC18C;&#xC790;&#xB294; &#xB2E8;&#xC77C; &#xCC44;&#xB110; &#xD574;&#xC0C1;&#xB3C4; &#xD5C8;&#xC6A9; &#xD558;&#xB3C4;&#xB85D; &#xCDA9;&#xBD84;&#xD788; &#xB0AE;&#xC740;. &#xC131;&#xACF5;&#xC801;&#xC778; &#xCC44;&#xB110; &#xC0BD;&#xC785;, &#xC18C;&#xD3EC; &#xAD00;&#xB828; &#xB41C; &#xBCF5;&#xC7A1; &#xD55C; &#xD3EC;&#xC720;&#xB958; &#xCC44;&#xB110; (&#xC778;&#xAC04;&#xC758; &#xAE00;&#xB9AC;&#xC2E0; &#xC218;&#xC6A9; &#xCCB4;, GlyR) &#xBFD0;&#xB9CC; &#xC544;&#xB2C8;&#xB77C; &#xAC16;&#xACE0; ionophore (alamethicin)&#xC73C;&#xB85C; &#xAD00;&#xCC30; &#xD588;&#xB2E4;. &#xC9C0;&#xC9C8; &#xC6A9; &#xB9E4;&#xC5D0;&#xB294; &#xC2A4;&#xD540; &#xCF54;&#xD305; &#xD558; &#xC5EC; &#xC6E8;&#xC774;&#xD37C;&#xC5D0; &#xC801;&#xC6A9;, &#xAC74;&#xC870;, &#xADF8;&#xB9AC;&#xACE0; &quot;&#xC0CC;&#xB4DC;&#xC704;&#xCE58;&quot;&#xB294; &#xB098;&#xC774;&#xD2B8; &#xB77C; &#xC774;&#xB4DC; &#xC544;&#xB798;&#xC640; &#xC704;&#xC758; agarose&#xC758; &#xB808;&#xC774;&#xC5B4; &#xC0AC;&#xC774; &#xC5B4;&#xB514; bilayer &#xD615;&#xC131; &#xD558;&#xB294; &quot;&#xD578; &#xC988; &#xD504;&#xB9AC;&quot; &#xC811;&#xADFC; &#xBC29;&#xC2DD;&#xC744; &#xD14C;&#xC2A4;&#xD2B8;&#xB3C4; &#xD588;&#xB2E4;. &#xADF8;&#xB7EC;&#xB098; &#xC804;&#xAE30;&#xC801; &#xD2B9;&#xC131; bilayers&#xC640; &#xC77C;&#xCE58; &#xD588;&#xB2E4; &#xAD00;&#xCC30; &#xBC0F; alamethicin &#xB179;&#xC74C; &#xAC00;&#xC838;&#xC628;,&#xC774; &#xBC29;&#xBC95;&#xC740; vesicles &#xD3EC;&#xC720;&#xB958; &#xCC44;&#xB110;&#xC774; &#xB4E4;&#xC5B4; &#xC788;&#xB294; &#xD4E8;&#xC804;&#xC640; &#xD638;&#xD658; &#xB418;&#xC9C0; &#xC54A;&#xC2B5;&#xB2C8;&#xB2E4;.

Agarose &#xC9C0;&#xC6D0; &#xC2E4;&#xB9AC;&#xCF58; orifices&#xC5D0; &#xC774;&#xC628; &#xCC44;&#xB110;&#xC758; &#xC7AC;&#xAD6C;&#xC131;.

Una oblea de silicio con ocho orificios microfabricated individualmente direccionables se utiliz&#xF3; para la reconstituci&#xF3;n del canal de iones y la grabaci&#xF3;n de un solo canal. Un spin-on fluoropol&#xED;mero creado un aislante, interfase hidrof&#xF3;bica que era m&#xE1;s estable que el silano. Capacidad total de las membranas fue &#x26;lt;10 pF, por lo que es f&#xE1;cil de evaluar la formaci&#xF3;n de dos capas por el cambio de capacitancia. Los orificios de 50 a 250 micras de di&#xE1;metro fueron probados para la facilidad y la estabilidad de la formaci&#xF3;n de dos capas, y s&#xF3;lo los&#x26;gt; 100 micras resultado en funci&#xF3;n del canal i&#xF3;nico. Bicapas se form&#xF3; sobre una capa de agarosa de apoyo mediante la aplicaci&#xF3;n de l&#xED;pidos en decano con una brocha, una segunda capa de agarosa podr&#xED;a entonces ser a&#xF1;adido para estabilizar la estructura y evitar la evaporaci&#xF3;n. Microfluidic pozos fueron construidos en placas de vidrio para la facilidad de montaje y visualizaci&#xF3;n de flujo de fluido, as&#xED; como microscop&#xED;a de alta resoluci&#xF3;n para los estudios que utilizan l&#xED;pidos fluorescentes y canales. Los microflu&#xED;dica constaba de forma reversible unido caucho de silicona (PDMS), de modo que todo el dispositivo podr&#xED;a ser lavados y reutilizados. Ruido total el&#xE9;ctrica en el dispositivo era lo suficientemente bajo como para permitir un solo canal de resoluci&#xF3;n. El &#xE9;xito de las inserciones de canal se observaron con un ion&#xF3;foro auto-montaje (alamethicin), as&#xED; como un complejo, ves&#xED;cula asociada a canal de mam&#xED;feros (humano receptor de glicina, GlyR). Un &#x26;quot;manos libres&#x26;quot; enfoque a la formaci&#xF3;n de bicapa se ensay&#xF3; tambi&#xE9;n, donde los l&#xED;pidos en disolvente se aplic&#xF3; a la oblea por recubrimiento por rotaci&#xF3;n, se sec&#xF3; y, a continuaci&#xF3;n &#x26;quot;sandwich&#x26;quot; entre las capas de agarosa por encima y por debajo del nitruro. Las propiedades el&#xE9;ctricas consistentes con bicapas se observaron y grabaciones alamethicin se obtuvieron, sin embargo este m&#xE9;todo no es compatible con la fusi&#xF3;n de ves&#xED;culas que contienen canales de mam&#xED;feros.

La reconstituci&#xF3;n de los canales i&#xF3;nicos en la agarosa apoyados por orificios de silicio

Digital holographic microscopy is an ideal tool for investigation of microbial motility. However, most designs do not exhibit sufficient spatial resolution for imaging bacteria. In this study we present an off-axis Mach-Zehnder design of a holographic microscope with spatial resolution of better than 800 nm and the ability to resolve bacterial samples at varying densities over a 380 μm × 380 μm × 600 μm three-dimensional field of view. Larger organisms, such as protozoa, can be resolved in detail, including cilia and flagella. The instrument design and performance are presented, including images and tracks of bacterial and protozoal mixed samples and pure cultures of six selected species. Organisms as small as 1 μm (bacterial spores) and as large as 60 μm (Paramecium bursaria) may be resolved and tracked without changes in the instrument configuration. Finally, we present a dilution series investigating the maximum cell density that can be imaged, a type of analysis that has not been presented in previous holographic microscopy studies.

A Mach-Zender digital holographic microscope with sub-micrometer resolution for imaging and tracking of marine micro-organisms.

The kinetics of toxicity of doxorubicin (Dox) and gold nanoparticle-conjugated doxorubicin (Au-Dox) were investigated in cultured B16 melanoma cells and cardiomyocytes using real-time cell-growth imaging. Both bolus exposure and continuous exposure were used. Modeling of the growth curve dynamics suggested patterns of uptake and/or expulsion of the drug that were different for the different cell lines and exposures. Dox alone in B16 cells fit to a model of slow drug buildup, whereas Au-Dox fit to a pattern of initial high drug efficacy followed by a decrease. In cardiomyocytes, the best fit was to a model of increasing drug concentration which then began to decrease, consistent with breakdown of the doxorubicin in solution. Cardiomyocytes were more sensitive than B16 cells to Dox alone (IC50 123 ± 2 nM vs. 270 ± 2 nM with continuous exposure), but were dramatically less sensitive to Au-Dox (IC50 1 ± 0.1 μM vs. 58 ± 5 nM with continuous exposure). Bolus exposure for 40 min led to significant cell death in B16 cells but not in cardiomyocytes. Fluorescence lifetime imaging (FLIM) showed different patterns of uptake of Au-Dox in the two cell types that explained the differential toxicity. While Au-Dox concentrated in the nuclei of B16 cells, it remained endosomal in cardiomyocytes. These results suggest that stable conjugates of nanoparticles to doxorubicin may be useful for treating resistant cancers while sparing healthy tissue.

Differential toxicity of gold-doxorubicin in cancer cells vs. cardiomyocytes as measured by real-time growth assays and fluorescence lifetime imaging microscopy (FLIM).

Fluorescence is not frequently used as a tool for investigating the photocycles of rhodopsins, largely because of the low quantum yield of the retinal chromophore. However, a new class of genetically encoded voltage sensors is based upon rhodopsins and their fluorescence. The first such sensor reported in the literature was the proteorhodopsin optical proton sensor (PROPS), which is capable of indicating membrane voltage changes in bacteria by means of changes in fluorescence. However, the properties of this fluorescence, such as its lifetime decay components and its origin in the protein photocycle, remain unknown. This paper reports steady-state and nanosecond time-resolved emission of this protein expressed in two strains of Escherichia coli, before and after membrane depolarization. The voltage-dependence of a particularly long lifetime component is established. Additional work to improve quantum yields and improve the general utility of PROPS is suggested.

Initial photophysical characterization of the proteorhodopsin optical proton sensor (PROPS).

Sea ice is an analog environment for several of astrobiology's near-term targets: Mars, Europa, Enceladus, and perhaps other Jovian or Saturnian moons. Microorganisms, both eukaryotic and prokaryotic, remain active within brine channels inside the ice, making it unnecessary to penetrate through to liquid water below in order to detect life. We have developed a submersible digital holographic microscope (DHM) that is capable of resolving individual bacterial cells, and demonstrated its utility for immediately imaging samples taken directly from sea ice at several locations near Nuuk, Greenland. In all samples, the appearance and motility of eukaryotes were conclusive signs of life. The appearance of prokaryotic cells alone was not sufficient to confirm life, but when prokaryotic motility occurred, it was rapid and conclusive. Warming the samples to above-freezing temperatures or supplementing with serine increased the number of motile cells and the speed of motility; supplementing with serine also stimulated chemotaxis. These results show that DHM is a useful technique for detection of active organisms in extreme environments, and that motility may be used as a biosignature in the liquid brines that persist in ice. These findings have important implications for the design of missions to icy environments and suggest ways in which DHM imaging may be integrated with chemical life-detection suites in order to create more conclusive life detection packages.

A Submersible, Off-Axis Holographic Microscope for Detection of Microbial Motility and Morphology in Aqueous and Icy Environments.

Digital holographic microscopy (DHM) is an emerging imaging technique that permits instantaneous capture of a relatively large sample volume. However, large volumes usually come at the expense of lower spatial resolution, and the technique has rarely been used with prokaryotic cells due to their small size and low contrast. In this paper we demonstrate the use of a Mach-Zehnder dual-beam instrument for imaging of labeled and unlabeled bacteria and microalgae. Spatial resolution of 0.3 μm is achieved, providing a sampling of several pixels across a typical prokaryotic cell. Both cellular motility and morphology are readily recorded. The use of dyes provides both amplitude and phase contrast improvement and is of use to identify cells in dense samples.

Improved Tracking and Resolution of Bacteria in Holographic Microscopy Using Dye and Fluorescent Protein Labeling.

Detection of extant microbial life on Earth and elsewhere in the Solar System requires the ability to identify and enumerate micrometer-scale, essentially featureless cells. On Earth, bacteria are usually enumerated by culture plating or epifluorescence microscopy. Culture plates require long incubation times and can only count culturable strains, and epifluorescence microscopy requires extensive staining and concentration of the sample and instrumentation that is not readily miniaturized for space. Digital holographic microscopy (DHM) represents an alternative technique with no moving parts and higher throughput than traditional microscopy, making it potentially useful in space for detection of extant microorganisms provided that sufficient numbers of cells can be collected. Because sample collection is expected to be the limiting factor for space missions, especially to outer planets, it is important to quantify the limits of detection of any proposed technique for extant life detection. Here we use both laboratory and field samples to measure the limits of detection of an off-axis digital holographic microscope (DHM). A statistical model is used to estimate any instrument's probability of detection at various bacterial concentrations based on the optical performance characteristics of the instrument, as well as estimate the confidence interval of detection. This statistical model agrees well with the limit of detection of 10(3) cells/mL that was found experimentally with laboratory samples. In environmental samples, active cells were immediately evident at concentrations of 10(4) cells/mL. Published estimates of cell densities for Enceladus plumes yield up to 10(4) cells/mL, which are well within the off-axis DHM's limits of detection to confidence intervals greater than or equal to 95%, assuming sufficient sample volumes can be collected. The quantitative phase imaging provided by DHM allowed minerals to be distinguished from cells. Off-axis DHM's ability for rapid low-level bacterial detection and counting shows its viability as a technique for detection of extant microbial life provided that the cells can be captured intact and delivered to the sample chamber in a sufficient volume of liquid for imaging. Key Words: In situ life detection-Extant microorganisms-Holographic microscopy-Ocean Worlds-Enceladus-Imaging. Astrobiology 17, 913-925.

Digital Holographic Microscopy, a Method for Detection of Microorganisms in Plume Samples from Enceladus and Other Icy Worlds.

We propose an automated wavelet-based method of tracking particles in unreconstructed off-axis holograms to provide rough estimates of the presence of motion and particle trajectories in digital holographic microscopy (DHM) time series. The wavelet transform modulus maxima segmentation method is adapted and tailored to extract Airy-like diffraction disks, which represent bacteria, from DHM time series. In this exploratory analysis, the method shows potential for estimating bacterial tracks in low-particle-density time series, based on a preliminary analysis of both living and dead Serratia marcescens, and for rapidly providing a single-bit answer to whether a sample chamber contains living or dead microbes or is empty.

Jay L. Nadeau

Department of Medical Engineering

California Institute of Technology

Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)

Jay L. Nadeau

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Medical Engineering

California Institute of Technology

Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)

Department of Medical Engineering