Multiphoton lithography with protein photoresists.

Recently, 2D/3D direct laser writing has attracted increased attention due to its broad applications ranging from biomedical engineering to aerospace. 3D nanolithography of water-soluble protein-based scaffolds have been envisioned to provide a variety of tunable properties. In this paper, we present a functional protein-based photoresist with tunable mechanical properties that is suitable for multiphoton lithography (MPL). Through the use of methacrylated streptavidin or methacrylated bovine serum albumin in combination with polyethylene glycol diacrylate or methacrylated hyaluronic acid as crosslinkers and a vitamin-based photoinitiator, we were able to write two- and three-dimensional structures as small as 200 nm/600 nm lateral/axial features, respectively. We also demonstrated that Young's modulus can be tuned by the photoresist composition, and we were able to achieve values as low as 40 kPa. Furthermore, we showed that Young's modulus can be recovered after drying and rehydration (i.e. shelf time determination). The retained biological functionality of the streptavidin scaffolds was demonstrated using fluorescently labelled biotins. Using single-molecule fluorescence microscopy, we estimated the density of streptavidin in the written features (1.8 ± 0.2 × 105 streptavidins per 1.00 ± 0.05 µm³ of feature volume). Finally, we showed applicability of our 2D scaffold as a support for a fluorescence absorbance immuno-assay (FLISA), and as a delivery platform of extracellular vesicles to HeLa cells.

Evaluation of pro-oxidant antioxidant balance in retinopathy of prematurity.

INTRODUCTION: Retinopathy of prematurity (RoP) is a vasoproliferative disorder caused by the abnormal development of retinal vessels in premature neonates. It is one of the major causes of childhood blindness, which is increasing with the increasing survival rate of low birth weight and premature neonates. This study has aimed to evaluate the role of oxidative stress and peroxidant antioxidant balance (PAB) in the pathogenesis and prediction of RoP. MATERIALS AND METHODS: A total of 154 neonates weighing <1500 g admitted at the NICU of Ghaem Hospital, Mashhad, Iran, were enrolled in this cross-sectional study between 2018 and 2020. Blood samples were collected on the first day of birth to assess the peroxidant and antioxidant balance. The demographic, prenatal, and clinical course and postnatal problems were also recorded. The neonates were examined for RoP and divided into control (healthy) and affected (ROP) groups. RESULTS: There were significant differences between the two groups in gestational age, duration of oxygen therapy, and first and fifth minute Apgar score (P < 0.005). The mean PAB in infants without and with ROP was 19.79 HK (Hamidi-Koliakos) and 38.45 HK, respectively (P < 0.0001). Also, the mean PAB in neonates with ROP grade 1 and 2 was 36.69 HK and 45.53 HK, respectively (P = 0.002). CONCLUSION: According to our findings, the PAB level can be helpful in predicting ROP incidence. With increasing PAB, the possibility of ROP severity will increase.