Gold nanoparticles have a high potential to be a treatment of diseases by their specific drug delivery properties and multivalent receptor stimulation. For the present project, spherical gold nanoparticles were synthesised and functionalised with the muscarinic receptor antagonist atropine (Au-MUDA-AT NPs). The diameter of the gold core could precisely be controlled by using different synthetic methods and reducing agents resulting in functionalised gold nanoparticles with diameters ranging from 8 to 16 nm. The ability to interact with intestinal muscarinic receptors is size-dependent. When using intestinal chloride secretion induced by the stable acetylcholine derivative, carbachol, as read-out, the strongest inhibition, i.e. the most efficient blockade of muscarinic receptors, was observed with 13 nm sized Au-MUDA-AT NPs. Functional experiments indicate that Au-MUDA-AT NPs with a diameter of 14 nm are able to pass the intestinal mucosa in a time-dependent manner after administration to the intestinal lumen. For example, luminally administered Au-MUDA-AT NPs inhibited contractions of the small intestinal longitudinal muscle layer induced by electrical stimulation of myenteric neurons. A similar inhibition of basolateral epithelial receptors was observed after luminal administration of Au-MUDA-AT NPs when using carbachol-induced chloride secretion across the intestinal epithelium as a test system. Thus, Au-MUDA-AT NPs might be a therapeutic tool for the modulation of intestinal secretion and motility after oral application in the future.

METHODOLOGICAL INFORMATION about the original data sets (unprocessed csv files):
The CCh-induced change of isometric tension (in gram) after administration of Au-MUDA-AT NPs (5 pmol/l at the serosal side of rat jejunum, 14 nm diameter) was recorded in organ bath experiments. In the corresponding control experiments, equivalent volumes of buffer were applied instead of Au-MUDA-AT NPs.
The organ bath chamber (volume 10 ml) was filled with carbogen-gassed buffer solution and warmed up to 37 °C. At the beginning of each experiment, the pre-tension was set to 2 g. After the manual reduction of the pre-tension to 1 g, NPs or buffer were applied and incubated for at least 20 minutes, before carbachol (500 nmol/l) was administered to the serosal side of rat jejunum. At the end of each, the chamber solution was washed with buffer solution three times and potassium chloride (15 mmol/l at the serosal side) served as viability control.

DATA-SPECIFIC INFORMATION FOR: Data_not_shown_Au-MUDA-AT_NPs.csv
1. Number of records (columns): 8
2. Important information:
The first column named "Marker" gives information about specific events (e.g. drug administration) during the experiment.
Markers in the file:
    0: No event
    1: Manual reduction of pre-tension to 1 g
    2: Serosal application of equivalent volumes of buffer instead of Au-MUDA-Atropine NPs
    3: Serosal application of Au-MUDA-Atropine NPs (5 pmol/l, 14 nm diameter)
    4: Serosal application of carbachol (500 nmol/l)
    5. Replacement of the whole chamber volume by buffer solution (washing)
    6: Serosal application of KCl (15 mmol/l) serving as viability control
The second column "Time" shows the time scale in 1 second steps. Time jumps occur due to synchronisation of the marker for all experiments.
Each following column is a single record of one incubated jejunal segment. The name of each record consists of the abbreviation of the name of the experimenter, the date on which the experiment was perfomed and in which organ bath chamber the tissue was incubated.
    For example: RMai19_03: R = Rebecca Classen performed this experiment, Mai19 = Experiment was performed on 19th March 2020, _03 = This jejunal segment was incubated in organ bath chamber number 3.

DATA-SPECIFIC INFORMATION FOR: Data_not_shown_No_Drug.csv
1. Number of records (columns): 8
2. Important information:
The first column named "Marker" gives information about specific events (e.g. drug administration) during the experiment.
Markers in the file:
    0: No event
    1: Manual reduction of pre-tension to 1 g
    2: Serosal application of equivalent volumes of buffer instead of Au-MUDA-Atropine NPs
    3: Serosal application of Au-MUDA-Atropine NPs (5 pmol/l, 14 nm diameter)
    4: Serosal application of carbachol (500 nmol/l)
    5. Replacement of the whole chamber volume by buffer solution (washing)
    6: Serosal application of KCl (15 mmol/l) serving as viability control
The second column "Time" shows the time scale in 1 second steps. Time jumps occur due to synchronisation of the marker for all experiments.
Each following column is a single record of one incubated jejunal segment. The name of each record consists of the abbreviation of the name of the experimenter, the date on which the experiment was perfomed and in which organ bath chamber the tissue was incubated.
    For example: RMai19_04: R = Rebecca Classen performed this experiment, Mai19 = Experiment was performed on 19th March 2020, _04 = This jejunal segment was incubated in organ bath chamber number 4.

DATA-SPECIFIC INFORMATION FOR: Supporting_Information_Synthesis_and_analysis_of_the_nanoparticles.docx
1. Number of figures: 10
TEM images: Suppl. Figure 1 (Au-Citrate NPs), Suppl. Figure 4 (Au-MUDA NPs), Suppl. Figure 7 (Au-MUDA-AT NPs)
TEM images were taken on a Zeiss LEO 912. (300 kV, LaB6 cathode) equipped with a GATAN digital camera.

UV/Vis spectra: Suppl. Figure 2 (Au-Citrate NPs), Suppl. Figure 5 (Au-MUDA NPs), Suppl. Figure 8 (Au-MUDA-AT NPs)
UV/Vis spectra were recorded with an UV-1600PC spectrophotometer from VWR. Elemental analyses for C, H, N and S were acquired by Mr. Dirk Pullem on a Eurolab EA Elemental Analyzer at the University of Cologne.

NMR spectra: Suppl. Figure 3 (Au-Citrate NPs), Suppl. Figure 6 (Au-MUDA NPs), Suppl. Figure 9 (Au-MUDA-AT NPs)
1H-NMR and 13C-NMR spectra were recorded on Bruker Avance 400 MHz (AV 400), Bruker Avance II 300 MHz (AV 300) and Bruker Avance II+ 600 MHz (AV II 600) spectrometers at the Institute of Organic Chemistry, University of Cologne. 1H-NMR data are reported as follows: chemical shifts (multiplicity [ppm], classification). Multiplicity is recorded as s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet. All spectra were displayed with the software MestReNova.

IR spectra: Suppl. Figure 10 (MUDA-AT, Au-MUDA-AT NPs)
IR measurements were performed on a Perkin Elmer FTIR-ATR (UATR TWO) at rt with a maximum resolution of 1 cm-1. Absorption bands are given in cm-1.