Black Phosphorus (BP) Nanodots for Potential Biomedical Applications.

Recently, the appeal of 2D black phosphorus (BP) has been rising due to its unique optical and electronic properties with a tunable band gap (≈0.3-1.5 eV). While numerous research efforts have recently been devoted to nano- and optoelectronic applications of BP, no attention has been paid to promising medical applications. In this article, the preparation of BP-nanodots of a few nm to <20 nm with an average diameter of ≈10 nm and height of ≈8.7 nm is reported by a modified ultrasonication-assisted solution method. Stable formation of nontoxic phosphates and phosphonates from BP crystals with exposure in water or air is observed. As for the BP-nanodot crystals' stability (ionization and persistence of fluorescent intensity) in aqueous solution, after 10 d, ≈80% at 1.5 mg mL(-1) are degraded (i.e., ionized) in phosphate buffered saline. They showed no or little cytotoxic cell-viability effects in vitro involving blue- and green-fluorescence cell imaging. Thus, BP-nanodots can be considered a promising agent for drug delivery or cellular tracking systems.

Improved cell viability of biocompatible nutrient-contained polymeric nanofibers.

Nanofibers containing cell nutrients (PGDs) were fabricated by mixing 5 wt% poly(epsilon-caprolactone) (P), 4 wt% gelatin (G), and 0-2.4 wt% Dulbecco's Modified Eagle's Medium (D). The contact angles showed a considerable decrease from 118.4 degrees on the P scaffold to 17.6 degrees on PGD1.6 (containing 1.6 wt% D). The weight loss ratios between PGD1.6 and the P nanofiber, and between PGD1.6 and the PG nanofiber by degradation after 28 days were approximately 3.1 and 1.4, respectively. The rate of cell proliferation on PGD1.6 was greater than that on the PG nanofiber by 14% and 38% for the exchanged and unexchanged culture media, respectively. The physicochemical measurement results showed that the PGDs exhibited enhanced hydrophilic properties and rapid biodegradation. The PGD nanofibers with increasing D content showed better conditions for long-term cell viability. The growth mechanism of the cells on the PGDs was explained by an attachment and growth process.

Advanced carbon dots via plasma-induced surface functionalization for fluorescent and bio-medical applications.

Multifunctional carbon-based nanodots (C-dots) are synthesized using atmospheric plasma treatments involving reactive gases (oxygen and nitrogen). Surface design was achieved through one-step plasma treatment of C-dots (AC-paints) from polyethylene glycol used as a precursor. These AC-paints show high fluorescence, low cytotoxicity and excellent cellular imaging capability. They exhibit bright fluorescence with a quantum yield twice of traditional C-dots. The cytotoxicity of AC-paints was tested on BEAS2B, THLE2, A549 and hep3B cell lines. The in vivo experiments further demonstrated the biocompatibility of AC-paints using zebrafish as a model, and imaging tests demonstrated that the AC-paints can be used as bio-labels (at a concentration of <5 mg mL-1). Particularly, the oxygen plasma-treated AC-paints (AC-paints-O) show antibacterial effects due to increased levels of reactive oxygen species (ROS) in AC-paints (at a concentration of >1 mg mL-1). AC-paints can effectively inhibit the growth of Escherichia coli (E. coli) and Acinetobacter baumannii (A. baumannii). Such remarkable performance of the AC-paints has important applications in the biomedical field and environmental systems.

An improved hydrophilicity via electrospinning for enhanced cell attachment and proliferation.

The wettability of electrospun poly(epsilon-caprolactone) (PCL) mats was improved by co-electrospinning with poly(vinyl alcohol) (PVA), by double-spinneret electrospinning method. The improved hydrophilicity of the hybrid PCL/PVA mats was confirmed by water contact angle measurement. The in vitro cell attachment on the hydrophobic PCL and hydrophilically modified PCL/PVA mats was compared by culture studies using human prostate epithelial cells (HPECs). The stability of water-soluble PVA component in the electrospun PCL/PVA mats was checked by thermogravimetric analysis and intensity of fluorescence material after immersion in water for 7 days. The images from scanning electron microscopy, field emission scanning electron microscopy, and optical microscopy showed that the attachment and proliferation rate of HPECs were improved by introducing PVA into the electrospun PCL mats.