Biotin conjugated bovine serum albumin bbsa

A microarray of 5936 (53 × 112) biotin-conjugated bovine serum albumin (BBSA, Sigma-Aldrich) is printed on an epoxy-functionalized glass slide (CapitalBio Corporation, Beijing, China) at a concentration of 7.6 μM in 1 × PBS. The spot diameter is around 150 μm and the center-to-center spacing between two adjacent spots is 250 μm. The microarray covers an area of 13 mm × 28 mm. We install a microarray slide in a fluidic assembly and image it with the TIR OI-RD scanning microscope. The printed microarray is washed in situ with 1 × PBS buffer to remove excess printed materials and is incubated in a solution of 7.6 μM bovine serum albumin (BSA, Sigma-Aldrich, Shanghai, China) for 30 min to cover the unprinted surface. We react mouse anti-biotin IgG (Jackson ImmunoResearch, West Grove, PA, USA) with the microarray as follows. With the microarray initially in 1 × PBS buffer, we replace the buffer with a solution of anti-biotin antibody at a flow rate of 5 mL/min for 18 s. Afterward, the flow rate is reduced to 0.05 mL/min and continues for 20 min (association phase of the reaction). We then replace the antibody solution with 1 × PBS buffer at the rate of 5 mL/min in 18 s, after which we reduce the flow rate to 0.05 mL/min and continue the flow for another 40 min (dissociation phase of the reaction).

FeSO₄·7H₂O (>99%), FeCl₃ (97%), NH₄OH, oleic acid (90%), myristic acid (>98%), and lauric acid (>98%) were purchased from Merk Schuchardt OHG (Hehenbrunn, Germany) and used without any further modification.
Neutravidin protein was obtained from Thermo Fischer Scientific (Waltham, MA, USA). 1-ethyl-3-[3-dimethylpropyl] carbodiimide (EDC), bovine serum albumin (BSA), biotin-conjugated bovine serum albumin (BBSA), n-hydroxysuccinimide (NHS), 2-(n-morpholino) ethanesulfonic acid (MES), and Tween20 were purchased from Sigma-Aldrich (Madrid, Spain). Glass fiber membranes (GFCP001000), used as sample pad and backing cards (HF000MC100), were purchased from Millipore (Darmstadt, Germany). Other materials used were nitrocellulose membranes (UniSart CN95, Sartorius, Spain) and absorbent pads (Whatman, Piscataway, NJ, USA).