In this experiment, a new amphiphilic chitosan-poly(lactide) graft copolymer was synthesized and characterized by IR, 1H-NMR, XRD, TGA. The obtained chitosan-poly (lactide) graft copolymer was used as the matrix material to prepare nanodroplets (NDs) encapsulating with liquid PFP by double-emulsion and solvent evaporation method. The resulting NDs were characterized by photon correlation spectroscopy and transmission electron microscopy (TEM). The biocompatibility was explored by cytotoxicity assay, cell migration assay and blood biochemistry analysis. The experiments of ultrasonic imaging in vitro and in vivo were carried out with a B-mode clinical ultrasound imaging system. The results of FI-IR and 1H-NMR confirmed the successful grafting reaction of polylactic acid(PLLA) to chitosan with a graft rate of 365%. The average size of the NDs was 101.1 ± 2.7 nm, with the polydispersity index (PDI) of 0.127 ± 0.020, and the zeta potential was −31.8 ± 1.5 mV. From the TEM results, NDs were highly dispersed and had a spherical shape with a distinct capsule structure. The NDs exhibited good stability during storage at 4°C. The NDs solution with different concentrations did not affect cell growth and showed good biocompatibility in cytotoxicity, cell migration and blood biochemistry studies. Under the irradiation of ultrasonic waves, the NDs formed an ultrasonic high signal, which could significantly enhance the ultrasound imaging of tumor tissue in vivo. Taken together, the NDs hold great potential for ultrasound imaging as a nanosized contrast agent.
Due to the low bioavailability and severe toxic side effects caused by the lack of selectivity of traditional chemotherapy drugs, the targeted delivery of chemotherapy drugs has become the key to tumor treatment. The activity and transmembrane potential of mitochondria in cancer cells were significantly higher than that of normal cells, making them a potential target for chemotherapeutic drug delivery. In this study, triphenylphosphine (TPP) based mitochondria targeting polylactic acid (PLLA) nanoparticles (TPP-PLLA NPs) were synthesized to improve the delivery efficiency of anticancer drugs. The carrier material was characterized by 1H NMR and FT-IR and 7-hydroxyl coumarin (7-HC) was successfully loaded into TPP-PLLA to form 7-HC/TPP-PLLA NPs. Further studies showed that TPP-PLLA NPs were primarily accumulated in the mitochondrial and 7-HC/TPP-PLLA NPs had higher antitumor activity. Taken together, our results indicated that TPP-PLLA NPs could be a promising mitochondria-targeted drug delivery system for cancer therapy.
The development of contrast agents that can be activated by multiple modes is of great significance for tumor diagnosis. In this study, the lactoferrin (Lf)-conjugated polylactic acid (PLLA) nanobubbles (Lf-PLLA NBs) were used to encapsulate liquid perfluoropentane (PFP) with the double emulsion method, creating PFP loaded (PFP/ Lf-PLLA) NBs for the ultrasound/magnetic resonance dual-modality imaging of subcutaneous tumor. The particle diameter and stability of nanobubbles were investigated by photon correlation spectroscopy. The biocompatibility of nanobubbles was preliminarily evaluated by cell proliferation and migration assay, hemolysis rate, and blood biochemistry analysis. A B-mode clinical ultrasound real-time imaging system was used to perform ultrasonic imaging in vivo. Magnetic resonance imaging in vivo was applied with a clinical 3.0 T magnetic resonance imaging (MRI) scanner system. The mean particle diameter of PFP/Lf-PLLA NBs was 320.2 ± 4.1 nm with a low polydispersity index (PDI, 0.145 ± 0.025), and the NBs were negatively charged (−11.4 ± 0.4 mV). The transmission electron microscopy (TEM) results showed that PFP/Lf-PLLA NBs exhibited highly monodispersed and possessed an obvious spherical structure of nanocapsules. Nanobubbles had good stability at 4°C. Different concentrations of the PFP/Lf-PLLA NBs solution had no effect on the cell in cytotoxicity and cell migration, and the results of hemolysis rate and blood biochemistry assay also indicated the good biocompatibility of NBs. On the ultrasound/magnetic resonance imaging of tumor-bearing mice, PFP/Lf-PLLA NBs showed significantly enhanced contrast ability of tumor tissue. Therefore, PFP/Lf-PLLA NBs had great potential to be a contrast agent for tumor dual-modality imaging in vivo.
This is an era where the rapid development of science and technology is accompanied by an aging population. The advancement of computer technology has brought new technologies to the elderly care industry, and related fields of elderly care robots have emerged as the times require. However, the operation of elderly care robots has always been a problem for older users. In view of such problems, this paper attempts to cut into the UI design of the touch screen interface of the elderly care robot. According to the characteristics of older users, aiming at their operational difficulties, and through research, new ideas and optimizations are put forward for the UI design of the existing elderly care service robot touch screen interface. So as to realize the further adaptation of product functions and older users.
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