Folate-Modified Photoelectric Responsive Polymer Microarray as Bionic Artificial Retina to Restore Visual Function.

A high-optical-resolution artificial retina system that accurately communicates with the optic nerve is the main challenge in the modern biological science and bionic field. Here, we developed a bionic artificial retina possessing phototransduction "cells" with measurements even smaller than that of the neural cells. Using the technique of micrometer processing, we constructed a pyramid-shape periodic microarray of a photoreceptor. Each "sensing cell" took advantage of polythiophene derivative/fullerene derivative (PCBM) as a photoelectric converter. Because folic acid played an essential role in eye growth, we particularly modified the polythiophene derivatives with folic acid tags. Therefore, the artificial retina could enlarge the contact area and even recognize the nerve cells to improve the consequence of nerve stimulation. We implanted the artificial retina into blinded rats' eyes. Electrophysiological analysis revealed its recovery of photosensitive function 3 months after surgery. Our work provides an innovative idea for fabricating a high-resolution bionic artificial retina system. It shows great potential in artificial intelligence and biomedicine.

[Pathological study on effects of preservative-free 1% lidocaine on lens epithelial cells of patients with age-related cataract].

OBJECTIVE: To assess whether preservative-free 1% lidocaine is capable of destroying the LECs in age-related cataract (ARC) in order to provide scientific basis for pursuing safe and effective drugs to eliminate LECs in cataract surgery. METHODS: Lens anterior capsule (LAC) specimens were collected from 75 patients (82 eyes) with age-related cataract (ARC), including forty males (44 eyes) and thirty-five females (38 eyes). The age range was 41 - 85 years, the mean age was 67.97 years. There were 34 cortical cataracts, 22 nuclear cataracts and 26 subcapsular cataracts. Capsule specimens were divided into 4 groups: balanced salt solution (BSS) group I and group II (exposed to BSS for 1 minute), lidocaine group (exposed to preservative-free 1% lidocaine for 1 minute) and the control group. Specimens were stained with trypan blue and alizarin red. Photomicrographs of each capsule were taken to observe the viability of LECs and to count the number of necrosis LECs. The pathologic changes of LECs were evaluated by histological methods (11 LAC, 22 pieces) as well as transmission and scanning electron microscopes (5 LAC, 10 pieces). In the control and BSS group I (23 LAC), one half of each capsule specimen was used for the control group and the other half was used for BSS group I. In lidocaine group and BSS group II (43 LAC), one half of each capsule specimen was used for lidocaine group and the other half was used for BSS group II. RESULTS: The rate of necrosis LECs of the anterior capsules in the control group and BSS group I was (56.19 +/- 2.71)% and (57.23 +/- 1.98)%, respectively. The rate of necrosis LECs of the capsules in lidocaine group and BSS group II was (99.86 +/- 8.22)% and (57.64 +/- 7.00)%, respectively. Matching t-test showed that the rate of necrosis LECs in lidocaine group was greater than that in the BSS group II (t = 27.6781, P = 0.0000). There was no significant difference in the number of necrosis LECs between the control group and BSS group I (t = 2.0693, P = 0.0505). There was also no significant difference between males and females; between different cataract, types and between varying age groups (P > 0.05). After irrigated with lidocaine, LECs showed vacuoles and detached from the capsule, and many cavities appeared between the LECs and the capsule. The capsules of BSS and control group showed a normal layer of LECs attached to the capsule. Under transmission and scanning electron microscopes, in lidocaine group, the junction between the LECs and between the cells and the capsule were destroyed; many cells detached from the capsule and the rest arranged loosely. Some LECs dented and many vacuoles emerged, resulting in destruction of the cellular structures. CONCLUSION: Preservative-free 1% lidocaine may loose the junction between LECs and between the cells and the capsule, and also destroy cellular structures, resulting in degeneration and necrosis of the LECs.

[Comparative study of gentamycin and povidone-iodine on eliminating the conjunctival bacteria].

OBJECTIVE: To study the efficacy of gentamycin, 0.5% povidone-iodine and 5.0% povidone-iodine in eliminating rate of positive conjunctival bacteria cultures and aqueous humor contamination, and to observe their adverse effects. METHODS: It was a comparative study. Three hundred patients (300 eyes) were randomized to three groups: gentamycin group, 0.5% povidone-iodine group and 5.0% povidone-iodine group. All patients received 1-day (6 times) topical application of 0.3% ofloxacin before surgery. Approximately 5 minutes before surgery, the conjunctival sac was irrigated with 5 - 8 ml gentamycin, 0.5% povidone-iodine or 5.0% povidone-iodine, correspondingly. Conjunctival cultures were obtained at the following time points: before receiving any topical medications; after application of 1-day topical 0.3% ofloxacin, before irrigating the conjunctival sac; immediately before surgery approximately 5 minutes after conjunctival sac irrigation and at the end of the surgery. Anterior chamber aspirates were obtained at the beginning of the surgery. Bacteria isolated were identified and antibiotic susceptibility was determined. The rate of positive conjunctival cultures among each group was compared and significance of the difference was tested with the Pearson chi-square test. RESULTS: Rate of positive conjunctival cultures before the conjunctival irrigation was 79.7%, 76.6% and 77.8% in the gentamycin group, 0.5% povidone-iodine group and 5.0% povidone-iodine group, respectively. The difference between these three groups was not statistically significant (chi2 = 0.28, P = 0.86). At the end of surgery, the rate of positive conjunctival cultures in these three groups was 11.7%, 8.3% and 6.3%, respectively. The difference between these three groups was also not statistically significant (chi2 = 1.74, P = 0.41). The average rate of anterior aqueous contamination was 4.9% and there was no significant difference among these three groups (P > 0.05). CONCLUSIONS: Both 0.5% povidone-iodine and 5.0% povidone-iodine using for irrigating conjunctival sac are safe. Gentamycin, 0.5% povidone-iodine and 5.0% povidone-iodine have similar effects on the reduction of the bacteria in conjunctival sac.

[Histopathological study of the effect of preservative-free 1% lidocaine on rabbit lens epithelial cells].

OBJECTIVE: To assess whether preservative-free 1% lidocaine is capable of loosing the junction between the rabbit lens epithelial cells (LECs) and between the cells and capsules and is capable of destroying the LECs, in order to provide scientific basis for pursuing safe and effective drugs to eliminate LECs in cataract surgery and to prevent capsular pacification. METHODS: Lens capsule specimens were collected from 29 rabbits (58 eyes) and divided into 3 groups: balanced salt solution (BSS) group (exposed to BSS for 1 minute), lidocaine group (exposed to preservative-free 1% lidocaine for 1 minute) and the control group. Specimens were stained with trypan blue and alizarin red. Photomicrographs of each capsule were taken to observe the viability of LECs and count the number of dead LECs. The histopathologic changes of LECs treated with lidocaine were evaluated by histological method and transmission electron microscope. RESULTS: The rate of dead LECs of the anterior and the equatorial lens capsules in control group was (1.51 +/- 0.39)%, and (1.52 +/- 0.32)%, respectively. The rate of dead LECs of the anterior and the equatorial lens capsules irrigated with BSS was (1.78 +/- 0.50)% and (1.77 +/- 0.47)%. The rate of dead LECs of the anterior and the equatorial lens capsules irrigated with preservative-free 1% lidocaine was (13.01 +/- 4.67)% and (9.59 +/- 3.35)%, respectively. The nested design ANOVA showed that the rate of dead LECs in the lidocaine group was greater than that in the control group or BSS group (P < 0.05), There was no significant difference in the number of dead cells between the anterior lens capsules and the equatorial lens capsules. After irrigated with lidocaine, cavities appeared ibetween the LECs and the capsule, cells detached from the capsule and showed vacuoles. The capsules of control group and BSS group showed a normal layer of LECs attached to the capsule. Under transmission electron microscope, in the lidocaine group, the junction between LECs and between the cell and the capsule were destroyed, many cells detached from the capsule and the rest arranged loosely. Some LECs dentes, and many vacuoles emerged, resulting in destruction of the cellular frame. CONCLUSION: Preservative-free 1% lidocaine may loose the junction between the LECs and between the cells and capsules, resulting in degeneration and death of the LECs.