The ability to pattern a surface with proteins on both the nanometer and micrometer scale has attracted considerable interest due to its applications in the fields of biomaterials, biosensors, and cell adhesion. Here we describe a simple particle lithography technique to fabricate substrates with hexagonally patterned dots of protein surrounded by a protein-repellant layer of poly(ethylene glycol) (PEG). Using this bottom-up approach, dot arrays of three different proteins (fibrinogen, P-selectin, and human serum albumin) were fabricated. The size of the protein dots (450 nm - 1.1 μm) was independent of the protein immobilized, but could be varied by changing the size of the latex spheres (diameter = 2 - 10 μm) utilized in assembling the lithographic bead monolayer. These results suggest that this technique can be extended to other biomolecules and will be useful in applications where arrays of protein dots are desired.

Objectives To assess the efficacy of a patient navigator intervention to decrease non-adherence to obtain audiological testing following failed screening, compared to those receiving the standard of care. Methods Using a randomized controlled design, guardian-infant dyads, in which the infants had abnormal newborn hearing screening, were recruited within the first week after birth. All participants were referred for definitive audiological diagnostic testing. Dyads were randomized into a patient navigator study arm or standard of care arm. The primary outcome was the percentage of patients with follow-up non-adherence to obtain diagnostic testing. Secondary outcomes were parental knowledge of infant hearing testing recommendations and barriers in obtaining follow-up testing. Results Sixty-one dyads were enrolled in the study (patient navigator arm=27, standard of care arm=34). The percentage of participants non-adherent to diagnostic follow-up during the first 6 months after birth was significantly lower in the patient navigator arm compared with the standard of care arm (7.4% versus 38.2%) (p=0.005). The timing of initial follow-up was significantly lower in the navigator arm compared with the standard of care arm (67.9 days after birth versus 105.9 days, p=0.010). Patient navigation increased baseline knowledge regarding infant hearing loss diagnosis recommendations compared with the standard of care (p=0.004). Conclusions Patient navigation decreases non-adherence rates following abnormal infant hearing screening and improves knowledge of follow-up recommendations. This intervention has the potential to improve the timeliness of delivery of infant hearing healthcare and future research is needed to assess the cost and feasibility of larger scale implementation.

Particle lithography is a relatively simple, inexpensive technique used to pattern inorganics, metals, polymers, and biological molecules on the micro- and nanometer scales. Previously, we used particle lithography to create hexagonal patterns of protein dots in a protein resistant background of methoxy-poly(ethylene glycol)-silane (mPEG-sil). In this work, we describe a simple heating procedure to overcome a potential limitation of particle lithography: the simultaneous change in feature size and center-to-center spacing as the diameter of the spheres used in the lithographic mask is changed. Uniform heating was used to make single-diameter protein patterns with dot sizes of approximately 2-4 or 2-8 μm, depending on the diameter of the spheres used in the lithographic mask, while differential heating was used to make a continuous gradient of dot sizes of approximately 1-9 μm on a single surface. We demonstrate the applicability of these substrates by observing the differences in neutrophil spreading on patterned and unpatterned protein coated surfaces.

We present a simple technique to fabricate hexagonally ordered quantum dot bioconjugate (QDBC) dot arrays on glass coverslips. We used particle lithography to create periodic holes in a layer of methoxy-poly(ethylene glycol)-silane and then adsorbed QDBCs into the holes. To demonstrate the versatility of this technique, we made separate periodic arrays of quantum dots (QDs) conjugated to three different biologically important molecules: biotin, streptavidin, and anti-mouse IgG. The diameters of the regions where the QDBCs adsorbed were 500-600 nm and independent of the QDBC patterned. The site density of the QDBCs in the patterned holes could be varied by simply adjusting the coating concentration of the QDBC solution. We demonstrate the applicability of these substrates by designing a QDBC-based binding assay with a working concentration range of several orders of magnitude and a sub-picomolar detection limit.

Current point-of-care (POC) screening of Coronavirus disease 2019 (COVID-19) requires further improvements to achieve highly sensitive, rapid, and inexpensive detection. Here we describe an immunoresistive sensor on a polyethylene terephthalate (PET) film for simple, inexpensive, and highly sensitive COVID-19 screening. The sensor is composed of single-walled carbon nanotubes (SWCNTs) functionalized with monoclonal antibodies that bind to the spike protein of SARS-CoV-2. Silver electrodes are silkscreen-printed on SWCNTs to reduce contact resistance. We determine the SARS-CoV-2 status via the resistance ratio of control- and SARS-CoV-2 sensor electrodes. A combined measurement of two adjacent sensors enhances the sensitivity and specificity of the detection protocol. The lower limit of detection (LLD) of the SWCNT assay is 350 genome equivalents/mL. The developed SWCNT sensor shows 100% sensitivity and 90% specificity in clinical sample testing. Further, our device adds benefits of a small form factor, simple operation, low power requirement, and low assay cost. This highly sensitive film sensor will facilitate rapid COVID-19 screening and expedite the development of POC screening platforms.