Enhanced Light Absorption in Porous Particles for Ultra-NIR-Sensitive Biomaterials

Transcription

1 Supporting Information Enhanced Light Absorption in Porous Particles for Ultra-NIR-Sensitive Biomaterials Jian Wang, Jing Zhao, Yanbo Li, Man Yang, Yu-Qiang Chang, Jian-Ping Zhang, Zhiwei Sun,*, Yapei Wang*, Department of Chemistry, Renmin University of China, Beijing, , P. R. China School of Public Health and Family Medicine, Capital Medical University, Beijing, , P. R. China Table of Contents 1. Materials and characterization methods 2. Preparation of PPy NPs, solid and porous particles 3. Assembly of paper chips 4. Light sensing tests of paper devices 5. Calculation of the photo thermal conversion efficiency 6. The evaluation of cytotoxicity of the particles 7. Intracellular localization of fluorescent CpG DNAs before and after incubation with the particles 8. Data section 1

2 1. Materials: Filter paper (thickness 200 μm, pore size ~ 2.5 μm) was purchased from Hangzhou Special-paper Co. Deionized water (18.2 MΩ cm -1 ) was obtained from a Milli-Q water-purification system. Polylactic acid (PLA, 180K) was purchased from Nature Work. FeCl 3 6H 2 O (99% purity) was obtained from Tianjin Fengchuan Chemical Reagent Technologies Co. Ltd. Dichloromethane (DCM), concentrated hydrochloric acid (HCl) solution (36-38 wt.%), and sodium hydroxide (NaOH) (96% purity) were provided by Beijing Chemical Reagent Company. Pyrrole (99%) was supplied by Lyntech. Bovine serum albumin (BSA, 98% purity) was purchased from LanYi Reagent Company. Characterization methods: A fluorescent microscope (Zeiss Axio Scope A1) was used to offer bright-field images of the particles in aqueous solution. The morphology of three types of particles at dry state, including PPy NPs, PPy@PLA particles and porous PPy@PLA particles were visualized on a scanning electron microscope at a voltage of 3.0 kv (SEM, JEOL-6700). The interfacial energy between DCM consisting of PLA and water with different ph values was measured via Pendant drop method on a dynamic contact angle meter and tensiometer (DCAT 21, DataPhysics Instruments GmbH). A commercial digital camera (Olympus, E-PM1) was used to acquire optical images of macroscopic objects. The temperature change of paper chips under light irraditon at diffirent power densities was examined on a thermal infared camera (RNO IR384). Differential Scanning Calorimetry (Mettler Toledo 822e calorimeter) was used to determine the specific heat capacity of the particles under nitrogen atmosphere. UV-Vis-NIR absorption spectrum of PPy NPs solution with the concentration of 300 µg/ml was collected on a SHIMADZU UV-3600 UV-VIS-NIR spectrophotometer. A thin layer of gold was sputted on the paper chips as 2

3 electrode by using a JCP-200 magnetron sputtering coating machine. Electrochemical workstation (CHI-660e Shanghai Chenhua Co.) was used to read the current change of the samples. Porosity of the porous particles was measured on a Mercury injection apparatus (Demo Autopore IV9500). 2. Preparation of PPy NPs, solid PPy@PLA, and porous PPy@PLA particles: The PPy@PLA porous particles were fabricated via a one-step emulsion method, as shown in Figure 1a. Briefly, an oil phase including pyrrole (99% purity, 100 μl) and PLA (5 wt.%, dissolved in dichloromethane, 1000 μl) was mixed with a water phase (3000 μl) including BSA (0.5 wt.%) and NaOH (0.2 wt.%). This mixture was vigorously stirred under a high-speed homogenization instrument (Fluko FA 25) at the speed of rpm for 3 min. The formed emulsion was held in a water bath at 40 C for 45 min to allow the evaporation of dichloromethane. The yielded porous PLA particles were rinsed by deionized water and centrifuged for three times to remove free BSA in the solution. Saturated FeCl 3 solution (200 μl) and BSA solution (500 μl, 0.5 wt.%) were subsequently added into the particles, leading to the interfacial polymerization of pyrrole on particle surfaces. Finally, the porous PLA particles coated with polypyrrole were washed by deionized water to remove unreacted FeCl 3. Solid PPy@PLA particles were prepared following the same protocol only by adjusting the water phase in the emulsion system at ph7. PPy NPs were also prepared by a emulsion method. Typically, 100 μl pyrrole dissolved in 1000 μl DCM was dispersed in 270 μl FeCl 3 aqueous solution which was subsequently added by 5 ml BSA (0.5 wt.%) to ensure the concentration of FeCl 3 is the same with the porous PPy@PLA particles. A stable emulsion was formed under a high-speed homogenization at the speed of rpm for 3 min. Pyrrole 3

4 was entirely polymerized into PPy NPs under stirring at 200 rpm at room temperature for 12 h. 3. Assembly of the paper devices: Particles dispersed in aqueous solution was deposited onto filter paper under the low-pressure suction. The particles were completely dried on paper after leaving them in open air for overnight. Afterwards, the paper coated with particles was cut into pieces with desirable size and shape, which was further deposited with two gold eletroodes (thickness~180 nm). The distance between two electrodes is 1.0 cm. 4. Light sensing tests of paper chips: The prepared paper device was bridged on a electrochemical workstation to examine its electrical response to NIR light. Each NIR illumination was lasted for 2 min with a range of power densities, from 0.01 W/cm 2 to 3.5 W/cm 2. At a given voltage of 1.0 V, light sensing tests were recorded with the conductivity change, ΔG/G 0, which was calculated by the normalized change of current, % I I /I 100 ΔG/G (1) where G 0 and I 0 are the initial conductivity and current before exposure to NIR light, and I is the current after exposure to NIR light. 5. Calculation of the photo-thermal conversion efficiency: The photo-thermal conversion efficiency (η) meets the equation (2) as is shown below. In this equation, Q represents the Joule heat of the generated by the NIR irradiation η Q Q (2) E P t E and P refer to the total energy and the power of the incident NIR light, respectively and t refers to the illumination time. The value of Q is determined by the specific heat (C p (T)), the surface temperature (T) and the mass (m) of the three different kinds of particles as is shown 4

5 in equation (3). Q T m C T dt (3) T 0 P The specific heat could be got from the Differential scanning calorimetry (DSC) curves shown in Figure S10 by establishing the relationship between specific heat (C p (T)) and heat flow (HF). The relationships between the two factors could be determined by the equations below. dh dt dt (4) dt dh HF (5) dt dh dt HF dt (6) dt dh dt C p C M (7) P HF (8) M β Here, β refers to the heating rate, H refers to the enthalpy of the samples and M refers to the mass of the samples being tested in the DSC experiment. Finally, we could get the relationships between the heat flow (HF) and the joule heat (Q) from the equation follows Q T HF m dt m = T0 M β M β T T0 HFdT (9) We could directly get the joule heat (Q) by just integrating the DSC curves from the given temperature interval as the mass of the particles on the paper (m), the heating rate (β) and the mass of the particles used in the DSC test (M) is constant. 6. The evaluation of cytotoxicity of the particles: The effect of particles on cell viability 5

6 was determined by MTT cell proliferation assay. Briefly, in a 96-well cell culture plate, of RAW264.7 cells were cultured overnight. After washing with fresh culture medium for three times, cells were treated with PLA@PPy or PPy NPs at different concentrations (0, 20, 40, 80, 160, 320 μg/ml). After 12 h and 24 h incubation, the medium was removed and replaced by serum-free media (200 μl per well containing 20 μl of 0.5 g/l MTT solution), then incubated for 2 to 4 hours until purple precipitate is visible. Supernatants were removed, and 150 μl of dimethylsulfoxide (DMSO) were added into each well. Spectrophotometric data were measured using SpectraMax M2 microplate reader (Molecular Devices, USA) at a wavelength of 490 nm. The cell viability (%) was calculated according to the formula: Cell viability (%) = experimental A490/control A %. 7. Intracellular localization of fluorescent CpG DNAs before and after incubation with the particles: In a 24-well glass bottom plate, of RAW264.7 cells were cultured overnight. After washing with fresh culture medium RAW264.7 cells were incubated at 37 C for 1 h with Alexa 488-conjugated CpG 1668 (5 -TCCATGACGTTCCTGATGCT- 3, 2 μm, Sangon Biotech, China) in the presence or absence of porous PLA@PPy particles (0.5 mg/ml). After oscillating the porous particles and DNA for 10 min, the mixture was illuminated by NIR light for 10 min to ensure the pores to be closed. The cells were stained with Hoechst (blue, Beyotime, China). The intracellular localization of CpG DNAs was observed under a confocal microscopy (Leica TCS SPV, Germany) and analyzed by the image software (Leica LAS AF, Germany). 6

7 9. Data section Figure S1. The interfacial energy between DCM consisting of PLA and water at different ph values by a Pendant drop method. b) The interfacial energy between pure DCM and water consisting of BSA at different ph values. Figure S2. The optical microscopy images of oil-in-water emulsion. Pure DCM in BSA aqueous solution at different ph condition a) ph=1, b) ph=7, c) ph=10, d) ph=12, respectively. Oil-water ratio is 1:3. 7

8 Figure S3. Optical microscopic images of the water-in-oil emulsion. Water in DCM consisting of PLA at (a) ph=7, (b) ph=12. c) The initial emulsion prepared at ph=7 (left) and the emulsion after 12 h (right). d) The initial emulsion prepared at ph=12 (left) and the emulsion after 12 h (right). Figure S4. Microscopic images of primary emulsion and their solidified particles with different oil-water ratios, (a, e) 1:2, (b, f) 1:3, (c, g) 1:4, (d, h) 1:5. (h-k) SEM images of the PLA particles of (e-h), respectively. ph is 12. 8

9 Figure S5. Optical microscopic images of primary emulsions and their solidified particles with the use of different surfactants: (a, d) PVA, (b, e) PVP, (c, f) BSA. (g-i) SEM images of PLA particles of (d-f), respectively. The oil-water ratio is 1:3. Figure S6. SEM image of the inner observation of nonporous PLA particles in an epoxy resin. 9

10 Figure S7. a) Optical images of porous PLA particles in aqueous solution after the polymerization of pyrrole on their surfaces. The volume of pyrrole encapsulated in the primary emulsion is 50 μl, 100 μl, and 200 μl, respectively. b) Three paper chips deposited with particles possessing different amount of polypyrrole on surface via the suction method under low pressure. Figure S8. SEM images of porous PLA particles with the use of different volume of pyrrole at the beginning of emulsification: a) 50 μl, b) 100 μl, c) 200 μl. 10

11 Figure S9. The influence of polypyrrole amount on the resistance and light sensing properties of the paper chips. a) Sheet resistance of three different paper chips with different polypyrrole originating from pyrrole with the volume of 50 μl, 100 μl, 200 μl, respectively. b) NIR light sensing test of two different paper chips with different polypyrrole amount, red line: 100 μl, black line: 200 μl. No electrical signal is collected for the paper chip of with low amount of polypyrrole (50 ul pyrrole) as it is insulating. Figure S10. DSC curves for the three different particles. a) PPy NPs, b) solid particles, c) porous particles. The shadow parts are the integrating area which are used to calculate the photo thermal conversion efficiency. 11

12 Figure S11. Cell viability of human umbilical vein endothelial cells (HUVECs) exposure to PPy NPs and porous particles with different concentrations ranging from 0 μg/ml to 320 μg/ml for a) 12 h, b) 24 h. Figure S12. The evaluation of porosity of the porous PLA particles. The porosity is 85.5% and the true density of PLA matrix is g/ml. The first peak of the differential pore volume curve refers to the interstitial volume among the packing particles, and the second peak represents the pore volume within the porous particles. The real pore volume is learned by removing the interstitial volume (5 ml/g) from the whole filling volume by mercury (9.8 ml/g), which is 4.8 ml/g. As the true density of solid particles is g/ml, the volume of PLA matrix is ml/g. Therefore, the total volume of particles (the sum of pore volume and polymer volume) is divided by the pore volume, giving the porosity of the particles, 4.8/( )=85.5%. 12

13 Figure S13. Fluorescent spectra of Alexa 488-labeled DNA (2 μm) a) before, b) after addition of porous particles (0.5 mg/ml) 13