The electrospray behaviors of saturated, substituted, and lacunary polyoxometalates(POMs) with classic Keggin and Dawson structures were investigated systematically by electrospray mass spectrometry(ESI-MS). The anion...The electrospray behaviors of saturated, substituted, and lacunary polyoxometalates(POMs) with classic Keggin and Dawson structures were investigated systematically by electrospray mass spectrometry(ESI-MS). The anions included Keggin [Si W12O40]4-, [Si W11O39]8-, [Si W10O36]8-, [Si W9O34]10-, Dawson [P2W18O62]6-, [P2W17O61]10-, and metal-substituted Keggin derivatives such as [PW11Mn O40]7-, [Si W10V2O40]6-, and [Ge W9Cu3O37]10-. Common species observed in the mass spectra arose from the protonation or cationization of either intact or dehydrated precursor ions. Compared to saturated and substituted POMs, lacunary POMs exhibited distinguished MS behaviors such as a much higher degree of cationization and dehydration of the bare polyoxoanions present in the mass spectra. In addition, some of these lacunary POMs were found to undergo subtle speciation change in solution. Freshly prepared solutions are suggested for synthetics for which lacunary POMs are starting materials. The advantages of the cation-exchange process which are prior to MS analysis are illustrated by an example.展开更多
Liver fibrosis, resulting from chronic liver damage and characterized by the accumulation of extracellular matrix (ECM) proteins, is a characteristic of most types of chronic liver diseases. The activation of hepatic ...Liver fibrosis, resulting from chronic liver damage and characterized by the accumulation of extracellular matrix (ECM) proteins, is a characteristic of most types of chronic liver diseases. The activation of hepatic stellate cells (HSC) is considered an essential pathological hallmark in liver fibrosis. Although nitric oxide (NO) can effectively induce HSC apoptosis, the systemic administration of NO is ineffective and may cause severe complications such as hypotension. To overcome this limitation, nanoparticles were designed to target HSCs and release NO locally under the exposure of near infrared light (NIR). To achieve this, upconversion nanoparticle (UCNP) cores were enveloped in mesoporous silica shells (UCNP@mSiO2), which were modified with hyaluronic acid (HA-UCNP@mSiO2) and Roussin’s black salt (RBS). HA molecules recognize and bind to CD44 proteins, which are overexpressed on activated HSCs. Under exposure to a 980-nm NIR laser, the UCNP cores convert the 980-nm wavelength into ultraviolet (UV) light, which then energizes the RBS (NO donors), resulting in an efficient release of NO inside of the HSCs. Once released, NO triggers HSC apoptosis and reverses the liver fibrosis. This targeted and controlled release method provides the theoretical and experimental basis for novel therapeutic approaches to treat hepatic fibrosis.展开更多
基金financially supported by the National Natural Science Foundation of China(21371025)the 111 Project(B07012)a Fundamental Research Grant(20121942006)by the Beijing Institute of Technology
文摘The electrospray behaviors of saturated, substituted, and lacunary polyoxometalates(POMs) with classic Keggin and Dawson structures were investigated systematically by electrospray mass spectrometry(ESI-MS). The anions included Keggin [Si W12O40]4-, [Si W11O39]8-, [Si W10O36]8-, [Si W9O34]10-, Dawson [P2W18O62]6-, [P2W17O61]10-, and metal-substituted Keggin derivatives such as [PW11Mn O40]7-, [Si W10V2O40]6-, and [Ge W9Cu3O37]10-. Common species observed in the mass spectra arose from the protonation or cationization of either intact or dehydrated precursor ions. Compared to saturated and substituted POMs, lacunary POMs exhibited distinguished MS behaviors such as a much higher degree of cationization and dehydration of the bare polyoxoanions present in the mass spectra. In addition, some of these lacunary POMs were found to undergo subtle speciation change in solution. Freshly prepared solutions are suggested for synthetics for which lacunary POMs are starting materials. The advantages of the cation-exchange process which are prior to MS analysis are illustrated by an example.
基金This work was supported by the American Heart Association(Nos.18TPA34230092 and 19EIA34660286 to K.C.)the National Natural Science Foundation of China(No.U1904149 to H.X.L.)+1 种基金National S&T Major Project of China(No.2018ZX10301201-008 to Z.G.R.)the High Technology Research and Development Program of Henan Province(No.20A320055 to H.X.L.).
文摘Liver fibrosis, resulting from chronic liver damage and characterized by the accumulation of extracellular matrix (ECM) proteins, is a characteristic of most types of chronic liver diseases. The activation of hepatic stellate cells (HSC) is considered an essential pathological hallmark in liver fibrosis. Although nitric oxide (NO) can effectively induce HSC apoptosis, the systemic administration of NO is ineffective and may cause severe complications such as hypotension. To overcome this limitation, nanoparticles were designed to target HSCs and release NO locally under the exposure of near infrared light (NIR). To achieve this, upconversion nanoparticle (UCNP) cores were enveloped in mesoporous silica shells (UCNP@mSiO2), which were modified with hyaluronic acid (HA-UCNP@mSiO2) and Roussin’s black salt (RBS). HA molecules recognize and bind to CD44 proteins, which are overexpressed on activated HSCs. Under exposure to a 980-nm NIR laser, the UCNP cores convert the 980-nm wavelength into ultraviolet (UV) light, which then energizes the RBS (NO donors), resulting in an efficient release of NO inside of the HSCs. Once released, NO triggers HSC apoptosis and reverses the liver fibrosis. This targeted and controlled release method provides the theoretical and experimental basis for novel therapeutic approaches to treat hepatic fibrosis.
