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diffi culty in the generation of core-shell NPs with a lipid shell containing various amounts of water, which governs the rigidity of the NPs; larger amounts of interfacial water would result in more fl exible NPs. [13][14][15] Microfl uidic platforms can generate lipid-polymer hybrid NPs via rapid reaction and precise manipulation of fl uids inside microchannels; [16][17][18][19][20] however, the fabrication of hybrid NPs with varying water content has not been achieved by microfl uidics. Here, we develop a two-stage microfl uidic platform that can assemble core-shell poly(lactic-co -glycolic acid) (PLGA)-lipid NPs in a single-step. [ 16,21 ] Lipid-covered PLGA NPs or liposomes that have the same size and surface properties, but varying rigidity as a result of tuning the interfacial water layer, can be realized using the same microchip. It enables us to explore how the rigidity of NPs differentially regulates the cellular uptake and to elucidate the intrinsic mechanism. It also allows the treatment of various diseases through the use of specifi c particles.Particle rigidity is tuned by varying the amounts of interfacial water between the PLGA core and lipid shell of the hybrid NPs; this is achieved by altering the injection order of the PLGA and lipid-poly(ethylene glycol) (PEG) organic solutions in the microfl uidic chip. The microfl uidic device shown in Scheme 1 consists of two stages: 1) The fi rst stage comprises three inlets and a straight synthesis microchannel; 2) The second stage is composed of one centered inlet and a spiral mixing channel (see Supporting Information (SI), Figure S1 for more details). We synthesized particles of varying water content and rigidity using the same chip but different order of the introducing reagents. In mode 1, the fi rst stage is used for generating PLGA NPs through interfacial precipitation, while the second stage forms lipid-coated NPs as a result of hydrophobic attraction between the lipid tail and PLGA (P-L NPs; Scheme 1 A, Figure S2 (SI)). In mode 2, we change the injection order by introducing the lipid solution at the fi rst stage and the PLGA solution at the second stage. In this way, lipids form into a liposome in aqueous solution at the fi rst stage, followed by re-assembly onto the surface of PLGA NPs at the second stage through effective mixing (P-W-L NPs; Scheme 1 B, Figure S2 (SI)). The throughput of NPs by a single chip is 41 mL h −1 (≈8 mg h −1 for P-W-L NPs, and ≈6.5 mg h −1 for P-L NPs). For both mode 1 and mode 2, transmission electron microscopy (TEM) images ( Figure 1 A; Figure S2, SI) show complete lipid coverage on the surface of PLGA NPs. The different injection order of the solutions may result in the presence of interfacial water between the PLGA core and lipid shell of the P-W-L NPs (mode 2) but not in P-L NPs (mode 1), which is confi rmed by cryogenic TEM (cryo-TEM Figure 1 B; see also SI). For the P-L NPs, the lipid shell is tightly attached to the PLGA core, while for the P-W-L Even though much research has shown that nanoparticles (NPs) ca...

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In recent years, gold nanoparticles (AuNPs) have drawn considerable research attention in the fields of catalysis, drug delivery, imaging, diagnostics, therapy and biosensors due to their unique optical and electronic properties. In this review, we summarized recent advances in the development of AuNP-based colorimetric and fluorescent assays for ions including cations (such as Hg(2+), Cu(2+), Pb(2+), As(3+), Ca(2+), Al(3+), etc) and anions (such as NO(2)(-), CN(-), PF(6)(-), F(-), I(-), oxoanions), and small organic molecules (such as cysteine, homocysteine, trinitrotoluene, melamine and cocaine, ATP, glucose, dopamine and so forth). Many of these species adversely affect human health and the environment. Moreover, we paid particular attention to AuNP-based colorimetric and fluorescent assays in practical applications.