An immune sandwich assay of carcinoembryonic antigen based on the joint use of upconversion phosphors and magnetic beads.

We herein report a sensitive and selective immunosensor for carcinoembryonic antigen (CEA) based on the joint use of upconversion phosphors (UCPs) and magnetic beads (MBs). UCPs as the signal probe were designed with a core-shell structure which provided a 40-fold enhancement of the luminescence intensity. Poly(acrylic acid) (PAA)-modified UCPs were covalently conjugated with the anti-CEA antibody (coating), and streptavidin functionalized magnetic beads were combined with another biotin-tagged anti-CEA antibody. With the assistance of a magnet, the as-formed immune sandwich in the presence of CEA can be readily separated from the assay matrix. The immunosensor showed a linear dynamic range for CEA within 0.05-20 ng mL(-1) in a buffered aqueous solution, and 0.1-20 ng mL(-1) in a human serum sample. The sensor was highly specific to CEA. Our results have suggested the potential application of the UCP-MB based immunoassay for CEA in clinical analysis.

Upconversion fluorescence resonance energy transfer biosensor with aromatic polymer nanospheres as the lable-free energy acceptor.

We report a new upconversion fluorescence resonance energy transfer (UC-FRET) biosensor using poly-m-phenylenediamine (PMPD) nanospheres as the energy acceptor in this paper. A single-stranded DNA (ssDNA) tagged with a sulfydryl group at the 5'-terminus was covalently linked to poly(ethylenimine) (PEI) functionalized upconversion phosphors (UCPs, the energy donor). Because of the π-rich electronic structure of PMPD, self-assembly of the donor and the acceptor was achieved through the π-π stacking interaction between ssDNA and PMPD. The fluorescence of the donor was quenched by the acceptor in a PMPD-concentration-dependent manner. A maximum quenching degree of 90% was acquired, which was among the highest levels of all previous reports. Upon the formation of double-stranded DNA (dsDNA) between the target DNA and the probe DNA, the energy acceptor was separated from the donor due to the weakened interaction between dsDNA and PMPD. The fluorescence of UCPs was accordingly restored, and a linear response was obtained with the target concentration ranging from 0.1 to 6.0 nM. The limit of detection was calculated as 0.036 nM, which was a highly competitive sensitivity. The sensor also showed high precision, pronounced specificity, and the applicability to complicated sample matrix (human serum). The UCPs-PMPD FRET sensing platform takes advantages of both the optical merits of the upconversion donors and the superquenching ability and good water-solubility of the aromatic polymer nanoparticles. This study will open the opportunity to develop a new class of UC-FRET biosensors.

A new species of the genus Amolops (Anura: Ranidae) from Yunnan, China.

A new species of the genus Amolops, Amolops tuanjieensis sp. nov., is described from Yunnan, China. The new species can be distinguished by the following characters: dorsolateral folds present; dorsal and ventral surfaces smooth; top of head and dorsum brown-red with irregular gray and dark spots; flank green; side of head black, from tip of snout, diffusing posteriorly to axilla, continuing as black streak below edge of dorsolateral fold; SVL 39.5-40.4 mm in males, 56.8-60.7 mm in females; tympanum distinct; supratympanic fold indistinct; vomerine teeth in two oblique rows between choanae, closer to each other than choanae; vocal sacs present; nuptial pads present; outer metatarsal tubercle absent, supernumerary tubercles absent; all fingertips expanded into discs; limbs dorsally brown with dark brown bars and irregular dark brown blotches.

A new species of the Amolops monticola group (Anura: Ranidae) from southwestern Yunnan, China.

We describe the new species Amolops mengdingensis sp. nov. from southwestern Yunnan, China. It belongs to the Amolops monticola species group and phylogenetically clusters together with Amolops akhaorum and Amolops archotaphus with strong support, although the relationships between these three species are not resolved. Distance between the new species and A. akhaorum is 4.7% and distance between the new species and A. archotaphus is 5.2% for 16S rRNA sequences. The new species is characterized by the following characters: distinct dorsolateral folds; side of the head dark brown with a white upper lip stripe extending to the axilla; dorsal surface smooth, except white spinules on posterior part of dorsolateral folds and above vent; top of head and dorsum green with dark spots in life; loreal region dark brown and flanks brown without any coloration of green; SVL 36.9-40.2 mm in males and 64.3 mm in female; two external subgular vocal sacs in males; vomerine teeth in two oblique ridges, separated by a small distance; pineal body absent; snout longer than eye diameter; internarial space broader than interorbital space; tympanum distinct, smaller than half of eye diameter; all fingertips expanded; two palmar tubercles; outer metatarsal tubercle absent; tibiotarsal articulation reaching beyond snout tip; near immaculate venter; limbs dorsally grayish brown with clear dark brown bars on hindlimbs; and velvety nuptial pads.

A new species of Zhangixalus (Anura: Rhacophoridae), previously confused with Zhangixalus smaragdinus (Blyth, 1852).

We describe a new species of Zhangixalus from southern Yunnan of China, Vietnam, and Thailand based on morphological and molecular evidence. The new species had been confused with Zhangixalus smaragdinus (Blyth, 1852) in the past. Zhangixalus pachyproctus sp. nov. can be distinguished from Z. smaragdinus morphologically by the protruding vent in adult males, large thick grey reticular mottles below the white stripe on flank, more oblique snout in profile and wider head, longer snout, greater internarial distance, larger tympanum and longer hindlimb. The new species can be distinguished from other species of Zhangixalus with green dorsum by the following combination of characters: body size larger (SVL of adult males: 74.2-83.3 mm; SVL of adult female: 102.4 mm); dorsum smooth; narrow white stripes along edge of the lower jaw, body sides, outer side of limbs and above the vent; absence of brown bands on canthus rostralis, upper eyelid and supratympanic fold; webbing between fingers and toes complete except between the first two fingers; and internal single subgular vocal sac. Phylogeny based on comparison of 16S rRNA sequences suggests that the new species is the sister taxon to Z. smaragdinus and the two species differ by 7.63% in the uncorrected pairwise distance of 16S sequences.