Photoelectric Bi2S3 Nanoparticle/Ti3C2Tx Nanosheet Heterojunction for Promotion of Nerve Cell Growth

Bismuth sulfide (Bi2S3) enabledus to transformlight signals into electrical signals via the photoelectric effect,which exhibited tremendous prospects on constructing wireless electricalstimulation for accelerating nerve regeneration. However, too rapidrecombination of photogenerated electron-hole pairs weakenedits photocurrent. Herein, the Bi2S3/Ti3C2Tx heterojunction was synthesizedby in situ growth of Bi2S3 nanoparticles onTi(3)C(2)T(x) nanosheetsand then mixed with poly-l-lactic acid (PLLA) powder to fabricatethe Bi2S3/Ti3C2Tx -PLLA conduit. At the heterojunction interfaces,Ti3C2Tx with a morepositive Fermi energy level could form interfacial potential differencewith Bi2S3 to promote electron-hole pairseparation. Meanwhile, Ti3C2Tx with excellent conductivity could provide channels for photogeneratedelectron transmission, thus facilitating the generation of the photocurrent.Photoluminescence and electrochemical impedance spectroscopy analysisindicated that electron-hole pair separation and electron transferwere enhanced. As a consequence, under near-infrared light radiation,the output photocurrent of Bi2S3/Ti3C2Tx -PLLA was increased from0.48 to 1.43 mu A compared to that of Bi2S3-PLLA. The enhanced photocurrent effectively promoted the differentiationof rat pheochromocytoma (PC12) into functional neurons by upregulatingextracellular Ca2+ influx. Therefore, the above resultsdemonstrated that this work provided a new perspective for wirelesselectrical stimulated nerve regeneration.

Automated summary

Bismuth sulfide (Bi2S3) can convert light signals into electrical signals via the photoelectric effect, but the rapid recombination of electron-hole pairs weakens its photocurrent. To address this issue, a Bi2S3/Ti3C2Tx heterojunction was synthesized and mixed with PLLA to fabricate a Bi2S3/Ti3C2Tx-PLLA conduit. The heterojunction improves electron-hole pair separation and electron transfer, leading to an increased photocurrent and enhanced differentiation of PC12 into functional neurons by upregulating Ca2+ influx.