Herein, we report on the preparation, purification, and preliminary characterization of multicolor fluorescent carbon nanoparticles (CNPs) obtained from the combustion soot of candles. The CNPs are small (< 2 nm) and water soluble. Different CNPs fluoresce with different colors under a single-wavelength UV excitation.Carbon-based nanomaterials, which include carbon nanotubes, fullerenes, and nanofibers, have promising applications in nanotechnology, biosensing, and drug delivery. [1][2][3] Recently, CNPs-a new class of carbon-based nanomaterials with interesting photoluminescence properties-were isolated. [4][5][6][7][8][9][10] These nanoparticles are either nanodiamonds or materials derived from carbon nanotubes and the laser ablation of graphite. Unlike fluorescent semiconductor nanocrystals (so-called quantum dots or Qdots), the fluorescent CNPs have only been poorly studied up to now because of the lack of preparative methods and separation techniques. Herein, we report a method for efficiently preparing and isolating fluorescent CNPs from a common carbon source, namely, candle soot.Our approach includes: 1) The preparation of fluorescent CNPs from the combustion soot of candles by means of an oxidative acid treatment and 2) the purification of the fluorescent CNPs by using polyacrylamide gel electrophoresis (PAGE). Incomplete combustion produces CNPs with diameters of 20-800 nm. [11,12] These particles strongly interact with each other to form agglomerates of several micrometers. To break down such inherent interactions and produce welldispersed, individual CNPs, we adopted an oxidative acid treatment, which is commonly used for the purification of carbon nanotubes.[13] This method is known to introduce OH and CO 2 H groups to the CNP surfaces, [14] thus making the particles become negatively charged and hydrophilic.The candle soot was collected by sitting a glass plate on top of smoldering candles. The soot contained mainly elemental carbon (elemental analysis: C 91.69 %, H 1.75 %, N 0.12 %, O (calculated) 4.36 %) and was hydrophobic and insoluble in common solvents. After refluxing the candle soot with 5 m HNO 3 , it turned into a homogeneous, black aqueous suspension. Upon centrifugation, the suspension separated into a black carbon precipitate and a light-brown supernatant, which exhibited yellow fluorescence when irradiated with UV light (312 nm). The black precipitate also contained fluorescent material (even after washing it several times). For maximum recovery of this fluorescent material, both the supernatant and the precipitate were neutralized and then extensively dialyzed against water. The neutralized candle soot exhibited an excellent dispersibility in water, which lasted several months.The same procedure failed to generate visible fluorescence if an oxidant, such as HNO 3 , was not present (this happened both in the presence and in the absence of surfactants, SDS). Another oxidant (30 % H 2 O 2 /AcOH = 2:1) resulted in blue fluorescence. The oxidative acid treatment might have three functions:...

In cancer patients, visual identification of sentinel lymph nodes (LNs) is achieved by the injection of dyes that bind avidly to endogenous albumin, targeting these compounds to LNs where they are efficiently filtered by resident phagocytes1,2. Here we translate this “albumin hitchhiking” approach to molecular vaccines, via the synthesis of amphiphiles (amph-vaccines) comprised of an antigen or adjuvant cargo linked to a lipophilic albumin-binding tail by a solubility-promoting polar polymer chain. Structurally-optimized CpG-DNA/peptide amph-vaccines exhibited dramatic increases in LN accumulation and decreased systemic dissemination relative to their parent compounds, leading to 30-fold increases in T-cell priming and enhanced anti-tumor efficacy while greatly reducing systemic toxicity. Amph-vaccines provide a simple, broadly-applicable strategy to simultaneously increase the potency and safety of subunit vaccines.

Vaccines based on recombinant proteins avoid toxicity and anti-vector immunity associated with live vaccine (e.g., viral) vectors, but their immunogenicity is poor, particularly for CD8+ T-cell (CD8T) responses. Synthetic particles carrying antigens and adjuvant molecules have been developed to enhance subunit vaccines, but in general these materials have failed to elicit CD8T responses comparable to live vectors in preclinical animal models. Here, we describe interbilayer-crosslinked multilamellar vesicles (ICMVs) formed by crosslinking headgroups of adjacent lipid bilayers within multilamellar vesicles. ICMVs stably entrapped protein antigens in the vesicle core and lipid-based immunostimulatory molecules in the vesicle walls under extracellular conditions, but exhibited rapid release in the presence of endolysosomal lipases. We found that these antigen/adjuvant-carrying ICMVs form an extremely potent whole-protein vaccine, eliciting endogenous T-cell and antibody responses comparable to the strongest vaccine vectors. These materials should enable a range of subunit vaccines and provide new possibilities for protein therapeutic delivery.

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